I’ve seen a few recent threads re: this. There were some problems with non-css Fab downloads and glitches with the automatic update feature.
In any case, I think they were registry errors. You may be all set with just updating to v.126.96.36.199, but you may want to consider running a registry cleaner first…your call.
I’ve used and recommended Regseeker for years, link in my sig.
There is a [B]Backup before deletion [/B]box, bottom left…enabled by default, do not untick this. I’ve never had a problem, but…
I also use CCleaner with good results.