If memory serves it is a PITA to change win 7 network group to 'workgroup'.
I wouldn't use "workgroup" anyway, but it seems to be easy to change. Go to Control panel-> System. The Computer name, domain, and workgroup settings are shown. On the right side is and option to Change settings. System properties opens, click on the Change button, and fill in the blanks (what you need should be obvious). A couple of OKs, and a reboot, should do the job.
Personally, I find it easy to get Win7 (Home, and Pro) to connect to SAMBA in eCS. Trying to connect to Win7, using EVFSGUI is a PITA, but it can be done. I just don't bother, and do it the other way.