While creating an rfc gateway service Class is not getting generated?

Hai friends,

while creating an rfc gateway service in sap netweaver gateway , the BOP class is not getting generated,when i click on generate.

Kindly help me in this aspect.for this i have attached the screen shot .

another error is coming once i generate the url its showing ,

<message>In the context of Data Services an unknown internal server error occured</message></error>.

Kindly help us in this issue.