wM call RFC error \"Control Framework: Fatal error - GU

Dear All,

Currenly, i have interface with SAP using RFC, some of the RFC actually calling BDC program, I got this error when i call that RFC
“Control Framework: Fatal error - GUI cannot be reached”

If that RFC running from SAP GUI is running well, but when calling from webMethods always response that error messag Err code : DC006, “Control Framework: Fatal error - GUI cannot be reached”.

But after I install SAP GUI in webMethods box server and turn on Advantage option SAP GUI On / Hidden. The problem solve, but how about the performance issue if still turn on SAP GUI option.

anybody can help give me advise, is it webMethods SAP Adapter problem or SAP problem ?

Thank you very much

Fernand Lesmana