I compared both folders and something strange caught my eye. In the older file, wich works, are a few files not included:
Hondsrugring.aiw
Hondsrugring.cam
Hondsrugring.gdb
Hondsrugring.scn
hondsrugring.tdf
hondsrugring_loading.jpg
Hondsrugring.tga
Hondsrugringmini.tga
Hondsrugringthmb.tga
also this file has been created.
Bulbglow.dds
and a few extra walls. (all Wall***.gmt files) But both are files i created in the latest version.
and the ta212.gmt file. wich i put in the folder because it couldn't find it.