hmm, in that case my problem is even stranger. I recorded my entire testframe under IE5.0 and everything works find except the logging in part. Now if I use the same script and run in under netscape it can log in and works almost as good as under IE5.0. Under IE5.5 it will log in but won't do anything else.
Are you using a derived Invoke, or are you simplely providing an ID and PWD in the frame file?
It's also posible that NS is using a dialog that silk will handle automatically when you have provided the passwor and ID in the frame, but IE is presenting a login page? if that is the case I would use a derived Invoke (as described in the User Guide) and build in a Switch Case based on browser type.