I am having issues when trying to create a sheet metal flange in SolidWorks 2010 & now 2011

After I define the flange & select OK I get an error  "This operation requires a fullly defined sketch"

I have had another more experienced user try to create a flange on this machine & it still fails.

This happens even if I open a part created by another user & edit feature & then try to accept - without changing anything.

I have another machine that I have tried this on & I can create/modify flanges OK, so it must be something in the config on this machine.

Any ideas would be greatly appreciated