I believe that rtffilt.dll is a rich text format filter/indexer used by apps like Word. I can't find any reference to it causing any problems like yours.
Settings.ini is just a text file used to store settings for Vista's sidebar - that file can be deleted or renamed if necessary - a new one will be created automatically the next time you run Windows. (Always best to just rename a file by adding "old" or similar to the name - that ways it's easy to restore if necessary)
Oddly enough, I found other reports of a corrupt sidebar settings.ini file causing bizarre behaviour in windows - like this one Windows Vista freezes and SFC cannot repair Settings.ini file - Microsoft Community
- in which the person couldn't even even move or resize ordinary windows or scroll the contents. That post also contains some useful advice on how to "clean boot" Windows - which may help you.
Just to clarify one thing - when I said "security" in reference to permissions, I'm not talking about security in the "Anti-virus" sense of the word - permissions are there to stop unauthorised changes to files. The "security" angle is not related to the original purpose of the file but the protection of it.