yipavibo.dll?
that doesnt sound like a legit/true dll file to me.
(if it where and it was a vista problem google would have gotten answers I found 1 result in google reffering to the malware Virtumonde)
I know some trojan/virus create Dll's with the most silly names.
in example the Virtumonde virus does that.
you notice any System slow downs or pop ups?
you might want to try to run a scan if possible. (what kind of AV are you running?)
HunterICX