The docs are correct.
Windows 7 should generate a version of 601.
Was the computer originally Windows XP and the upgraded to Windows 7 ?
The version number generated by EZGUI is based on a call to GetVersionEx. The major version number returned is multipled by 100 (ie. 6 x 100 = 600) and then the minor version value is added to it (ie. 600 + 1 = 601).
Here is some code from MSDN :http://msdn.microsoft.com/en-us/library/windows/desktop/ms724429(v=vs.85).aspx
and it shows Windows 7 as 601.