There "illegal characters in path" system message does not refer to a route path (the ones you generate with track viewer), but to the computer path of a file, in this case a .wav file recalled within an .sms file. So you should try to find out which .sms contains a faulty call to a .wav file...
I see from the log that there are also other errors in the content you are loading: there are missing tiles, see e.g. line
Warning: Ignoring missing tile D:\0.1 Eastern Roads\ROUTES\MONON-2\TILES\-04EE95C0.t
there are missing or incorrectly referenced shapes, like e.g.
Warning: w-011527+014394.w scenery object 61 with StaticFlags 00200180 references non-existent D:\0.1 Eastern Roads\Global\Shapes\A2t300r10d.s
there are missing or incorrectly referenced .wav files like e.g.
Warning: File 4449../../PM 1225/Sound/_0.wav missing from D:\0.1 Eastern Roads\trains\trainset\PRR_M1\sound
there are missing or incorrectly referenced .sms files like e.g.
Warning: File SOUND\OldenTrack2ex.sms missing from D:\0.1 Eastern Roads\ROUTES\MONON-2
Do also other users of Monon-2 get all these warnings? I second engmod's suspect that the route could be not correctly installed.