There's a bug in 5.08 which affects multi-dll applications.
Open \clarion6\3rdparty\template\nettalk.tpl
goto line around 175 - you should have something like
#!CALL(%SetCategoryLocation(ABC), 'NETTALK', 'NetTalk')
remove the ! at the front of the line to make
#CALL(%SetCategoryLocation(ABC), 'NETTALK', 'NetTalk')
You'll need to close clarion, open it again, and recompile from the data dll.
Sorry about the error.
I'll make a 5.09 build shortly.