"Illegal characters in path" when installing for the first time

```
Test-Path : Illegal characters in path.
At C:\Users\VnS\AppData\Local\Temp\Functions.psm1:810 char:21
+ if (Test-Path -Path $ThemePath) {
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (C:\Windows\system32:String) [Test-Path], ArgumentException
+ FullyQualifiedErrorId : DirArgumentError,Microsoft.PowerShell.Commands.TestPathCommand

Test-Path : Illegal characters in path.
At
C:\Windows\system32\WindowsPowerShell\v1.0\Modules\Microsoft.PowerShell.Archive\Microsoft.PowerShell.Archive.psm1:297
char:38
+ ... tionPathExists = Test-Path -Path $DestinationPath -PathType Container
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (C:\Windows\system32:String) [Test-Path], ArgumentException
+ FullyQualifiedErrorId : DirArgumentError,Microsoft.PowerShell.Commands.TestPathCommand

New-Item : Illegal characters in path.
At
C:\Windows\system32\WindowsPowerShell\v1.0\Modules\Microsoft.PowerShell.Archive\Microsoft.PowerShell.Archive.psm1:318
char:32
+ ... eatedItem = New-Item -Path $DestinationPath -ItemType Directory -Conf ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (C:\Windows\syst...Themes\WMPotify:String) [New-Item], ArgumentExceptio
n
+ FullyQualifiedErrorId : ItemExistsArgumentError,Microsoft.PowerShell.Commands.NewItemCommand
```

Getting this error ALWAYS when running any script (except uninstalling ones)

Reproduce a first-time installation on Windows, then inspect Functions.psm1 around line 810 and the reported Test-Path, New-Item, and Microsoft.PowerShell.Archive.psm1 calls. Compare the path values used by the installation scripts and confirm that every script except uninstall completes without the reported illegal-path errors.

Written by the indexing model from the issue text.