oort, the problem is in the plugin code. Did you read my latest email. It's about that in his log:
> d:/PROGRA~1/MODELI~1/RENDER~1/yafaray/bin/YAFARA~1.EXE -pp C:\Program Files\wings3d_1.5.4\lib\wings-1.5.4\plugins -f png wpc_yafaray-5980-3KCXSN.xml d:/tex
INFO: YafaRay 0.1.5
INFO: The plugin path is: C:\Program
INFO: Environment: Loading plugins ...
As it was done to the executable path - converted to short name, you need to do the same for the plugin path. That Program Files (with a blank space between) is causing the problem.
> d:/PROGRA~1/MODELI~1/RENDER~1/yafaray/bin/YAFARA~1.EXE -pp C:\Program Files\wings3d_1.5.4\lib\wings-1.5.4\plugins -f png wpc_yafaray-5980-3KCXSN.xml d:/tex
INFO: YafaRay 0.1.5
INFO: The plugin path is: C:\Program
INFO: Environment: Loading plugins ...
As it was done to the executable path - converted to short name, you need to do the same for the plugin path. That Program Files (with a blank space between) is causing the problem.