Install X-11 off of the restore disk that came with the iMac and try openoffice again.
You could also install crossover mac
http://www.codeweavers.com/products/cxmac/ and install your windows version of office without installing windows.
Or you could use Parallels Desktop
www.parallels.com and install a windows virtual machine to run office.
Lastly, you could get the Mac version of office and just use that!. She student/teacher version is cheap.