Some python perquisites for Linux missing

This is what happens om a fresh installed Ubuntu :


028,0
41.7844009399414,123.496002197266,0
51.894444,1.4825,0
-11.5842777778,47.2963888889,0
INFO MissionPlanner.MainV2 - Mainv2 ctor
INFO MissionPlanner.Utilities.Speech - TTS: init, mono = True
INFO MissionPlanner.MainV2 - Create FD
INFO MissionPlanner.GCSViews.FlightData - Ctor Start
INFO MissionPlanner.GCSViews.FlightData - Components Done
INFO MissionPlanner.GCSViews.FlightData - Tunning Graph Settings
INFO MissionPlanner.GCSViews.FlightData - HUD Settings
INFO MissionPlanner.Common - getModesList Called
INFO MissionPlanner.GCSViews.FlightData - Graph Setup
INFO MissionPlanner.GCSViews.FlightData - Map Setup
INFO MissionPlanner.MainV2 - Create FP
INFO MissionPlanner.MainV2 - Create SIM
INFO MissionPlanner.MainV2 - Create Python
Could not load signature of IronPython.Runtime.List:get_Item due to: Could not load file or assembly or one of its dependencies.
FATAL MissionPlanner.MainV2 - System.Reflection.TargetInvocationException: Failed to load language 'IronPython 2.7.5b1': Could not load type 'IronPython.Runtime.List' from assembly 'IronPython, Version=2.7.0.40, Culture=neutral, PublicKeyToken=7f709c5b713576e1'. ---> System.TypeLoadException: Could not load type 'IronPython.Runtime.List' from assembly 'IronPython, Version=2.7.0.40, Culture=neutral, PublicKeyToken=7f709c5b713576e1'.
at (wrapper managed-to-native) System.Reflection.MonoCMethod:InternalInvoke (System.Reflection.MonoCMethod,object,object[],System.Exception&)
at System.Reflection.MonoCMethod.InternalInvoke (System.Object obj, System.Object[] parameters) [0x00000] in :0
--- End of inner exception stack trace ---
at Microsoft.Scripting.Runtime.LanguageConfiguration.LoadLanguageContext (Microsoft.Scripting.Runtime.ScriptDomainManager domainManager, System.Boolean& alreadyLoaded) [0x00000] in :0
at Microsoft.Scripting.Runtime.DlrConfiguration.LoadLanguageContext (Microsoft.Scripting.Runtime.ScriptDomainManager manager, Microsoft.Scripting.Runtime.LanguageConfiguration config) [0x00000] in :0
at Microsoft.Scripting.Runtime.DlrConfiguration.TryLoadLanguage (Microsoft.Scripting.Runtime.ScriptDomainManager manager, AssemblyQualifiedTypeName providerName, Microsoft.Scripting.Runtime.LanguageContext& language) [0x00000] in :0
at Microsoft.Scripting.Runtime.ScriptDomainManager.GetLanguageByTypeName (System.String providerAssemblyQualifiedTypeName) [0x00000] in :0
at Microsoft.Scripting.Hosting.ScriptRuntime.GetEngineByTypeName (System.String assemblyQualifiedTypeName) [0x00000] in :0
at (wrapper remoting-invoke-with-check) Microsoft.Scripting.Hosting.ScriptRuntime:GetEngineByTypeName (string)
at IronPython.Hosting.Python.GetEngine (Microsoft.Scripting.Hosting.ScriptRuntime runtime) [0x00000] in :0
at IronPython.Hosting.Python.CreateEngine () [0x00000] in :0
at MissionPlanner.MainV2..ctor () [0x00000] in :0
CustomMessageBox thread calling Base Thread
CustomMessageBox thread running Base Thread
INFO MissionPlanner.MainV2 - myview width 1016 height 972
INFO MissionPlanner.MainV2 - this width 1024 height 999
INFO MissionPlanner.MainV2 - myview width 1732 height 972
INFO MissionPlanner.MainV2 - this width 1740 height 999
INFO MissionPlanner.Utilities.adsb - adsb connect loop
Open MissionPlanner.GCSViews.FlightData FlightData
Missing method UrlEncode in assembly /home/andre/Linux/MPb/MissionPlanner.Utilities.dll, type System.Web.HttpUtility
INFO MissionPlanner.GCSViews.FlightData - Activate Called
Missing method UrlEncode in assembly /home/andre/Linux/MPb/MissionPlanner.Utilities.dll, type System.Web.HttpUtility
Message: Could not load file or assembly 'System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.
Message: Could not load file or assembly 'System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.
CustomMessageBox thread calling Threadpool worker
CustomMessageBox thread calling Threadpool worker
CustomMessageBox thread running Threadpool worker
CustomMessageBox thread running Threadpool worker
[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
mono: Fatal IO error 11 (Resource temporarily unavailable) on X server :0.
mono: ../../src/xcb_io.c:179: dequeue_pending_request: Assertion `!xcb_xlib_unknown_req_in_deq' failed.
Stacktrace:

at <0xffffffff>
at (wrapper managed-to-native) System.Windows.Forms.X11Keyboard.XGetIMValues (intptr,string,intptr&,intptr) <0xffffffff>
at System.Windows.Forms.X11Keyboard.GetSupportedInputStyles (intptr) <0x0004b>
at System.Windows.Forms.X11Keyboard/c__Iterator0.MoveNext () <0x0004f>
at System.Windows.Forms.X11Keyboard.CreateXic (intptr,intptr) <0x0015b>
at System.Windows.Forms.X11Keyboard.CreateXicForWindow (intptr) <0x00037>
at System.Windows.Forms.X11Keyboard.FocusIn (intptr) <0x00087>
at System.Windows.Forms.XplatUIX11.SetFocus (intptr) <0x000b3>
at System.Windows.Forms.XplatUI.SetFocus (intptr) <0x0001f>
at System.Windows.Forms.ContainerControl.SendControlFocus (System.Windows.Forms.Control) <0x00083>
at System.Windows.Forms.Form.SetVisibleCore (bool) <0x0071f>
at System.Windows.Forms.Control.set_Visible (bool) <0x00032>
at (wrapper remoting-invoke-with-check) System.Windows.Forms.Control.set_Visible (bool) <0xffffffff>
at System.Windows.Forms.Application.RunLoop (bool,System.Windows.Forms.ApplicationContext) <0x002fb>
at System.Windows.Forms.Form.ShowDialog (System.Windows.Forms.IWin32Window) <0x008ab>
at System.Windows.Forms.Form.ShowDialog () <0x00013>
at (wrapper remoting-invoke-with-check) System.Windows.Forms.Form.ShowDialog () <0xffffffff>
at System.CustomMessageBox.ShowUI (string,string,System.Windows.Forms.MessageBoxButtons,System.Windows.Forms.MessageBoxIcon) <0x007c3>
at System.CustomMessageBox.Show (string,string,System.Windows.Forms.MessageBoxButtons,System.Windows.Forms.MessageBoxIcon) <0x0025b>
at System.CustomMessageBox.Show (string) <0x0001f>
at MissionPlanner.Program.handleException (System.Exception) <0x00353>
at MissionPlanner.Program.CurrentDomain_UnhandledException (object,System.UnhandledExceptionEventArgs) <0x0003b>
at (wrapper runtime-invoke) .runtime_invoke_void__this___object_object (object,intptr,intptr,intptr) <0xffffffff>

Reproduce the fresh-Ubuntu launch failure and start at MissionPlanner.MainV2, where Python.CreateEngine triggers the IronPython error. Trace the missing System.Web.HttpUtility dependency and the later X server failure. Done means the application launches without the reported missing-assembly, type-load, or X-server crash errors.

Written by the indexing model from the issue text.