"Unexpected error"

"Unexpected error"

Hi

One of our customers are reporting that when she filters in reports she gets a prompt saying "Error Occurred. We are sorry for the inconvenience" randomly.
I was asked to get some more info from the customer and it looks like it doesnt look like what report she is in matters. 
Neither does it look like the time of day matters.
The only thing we can see that she does is looking away for an unknown ammount of time. 
Like going for lunch or something, i don't know.

Is there a time-out for this? Anyone else had this issue? Also, can I configure the Time-out-timer to be "none"? ;)

Thanks in advance