You won't be able to use the Interop libraries if you can't install Office, because you will get the error you are describing.
It doesn't leave you with a lot of choices (I am assuming you are using word for modifying the document, rather than just doing something like printing it). So here they are as I see them:
- You can try to get them to allow Word to be installed.
- You could force the Office XML format for your reports and modify the XML directly.
- You could change the format to something else like crystal reports or Acrobat and then rewrite.
If you are simply PRINTING the document, you could use the
Word Viewer and
Compatability Pack and that might solve your problem.