I'm having the same problem. Apparently Adobe does not like Firefox. If you find a fix, please post.
In the last couple of weeks I have been regularly getting a pop up that says:
"Adobe Flash Player Update Service 11.3 r300 has encountered a problem and needs to close. We are sorry for the inconvenience."
Then there is the usual option of whether I wish to send this error report to Microsoft.
I've repaired Adobe reader a number of times under its help tab but the above pop up keeps appearing.
Can anyone tell me what is going on and what course of action I need to take? Thanks.