Cruise Control

What is your question?

I have a 1995 Nissan Sentra GXE (1.6L) manual, and the other day while driving I went over a big bump while I was on cruise control. All of the sudden the cruise contol light started to blink and then the 'check engine' light came on. I took it to a mechanic and he said that there is a problem with the cruise control. Now, when I drive I can sometimes put the car in cruise control while most of the time it does not do that. What do you think is wrong and why did it give me the problem this time while I have obviously gone over the bumps several times before? What kind of fix are we talking about here? What needs to be fixed and how much would it cost? Any suggestions, ideas or fixes? Thanks in advance!