what does it mean if i don't have that file there. the only files that show up are these two: data.dat and data.bak
The file opa11.dat occurs IF you have Word 2003 (or Office 2003) installed.
The files data.dat and data.bak occur if you have Word 2002, i.e. Word XP (or Office 2002, i.e. Office XP) installed.
If memory serves right data.dat has to do with product licence or product activation.
Would not think your problem is caused by a corrupt data.dat file, but rather guess you have a problem with the Office profile in question (presuming you have multiple user accounts on your system).
Hope this answers your specific question about the meaning of the non-existence of the file opa11.dat.