java.nio.file.NoSuchFileException

Running the binary via docker on QNAP TS-451 returns the following error:
_Edited to fix markdown formatting_
```
$ docker run jakewharton/plex-orphaned-files:1 --base-url http://:32400 --token --folder-mapping /media:/share/CACHEDEV1_DATA/Media
Exception in thread "main" java.nio.file.NoSuchFileException: \\192.168.1.250\Media\Courses
at sun.nio.fs.UnixException.translateToIOException(UnixException.java:86)
at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
at sun.nio.fs.UnixFileAttributeViews$Basic.readAttributes(UnixFileAttributeViews.java:55)
at sun.nio.fs.UnixFileSystemProvider.readAttributes(UnixFileSystemProvider.java:144)
at sun.nio.fs.LinuxFileSystemProvider.readAttributes(LinuxFileSystemProvider.java:99)
at java.nio.file.Files.readAttributes(Files.java:1737)
at java.nio.file.FileTreeWalker.getAttributes(FileTreeWalker.java:219)
at java.nio.file.FileTreeWalker.visit(FileTreeWalker.java:276)
at java.nio.file.FileTreeWalker.walk(FileTreeWalker.java:322)
at java.nio.file.FileTreeIterator.(FileTreeIterator.java:72)
at java.nio.file.Files.walk(Files.java:3574)
at java.nio.file.Files.walk(Files.java:3625)
at com.jakewharton.plex.OrphanedFilesCommand$run$1.invokeSuspend(main.kt:111)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:274)
at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:84)
at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59)
at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:38)
at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source)
at com.jakewharton.plex.OrphanedFilesCommand.run(main.kt:89)
at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:171)
at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:16)
at com.github.ajalt.clikt.core.CliktCommand.parse(CliktCommand.kt:395)
at com.github.ajalt.clikt.core.CliktCommand.parse$default(CliktCommand.kt:392)
at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:410)
at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:435)
at com.jakewharton.plex.OrphanedFiles.main(main.kt:169)
```

Start by reviewing the Docker invocation and the stack-trace locations in main.kt:89 and main.kt:111, then investigate how the folder mapping reaches Files.walk on the QNAP environment. Reproduce the reported command if possible; done means the mapped library path can be processed without the NoSuchFileException.

Written by the indexing model from the issue text.