ERROR in Aras 11 COULD NOT FIND DLL FILE – VB METHOD

when I developed a vb method, when I clicked on the "check syntax" button I have the following error message. I have also this error when a vb method is triggered. I don't know what to do because I can not use any vb scripting. The strange thing is that the name of the dll which is not found is never the same, it changed at each time I clicked on the button or triggered a vb method.