Application defined or object defined error

Hi guys,
I am at work generating some inventory reconciliation, when I am about to generate the final report an error message appeared on my screen, see below the screen shot.

Microsoft Office Access
Application-defined or object-defined error
This is my first time to encounter this error, what I did is just to restart my computer to have a refresh, since it was not properly shut down a while ago, when I am back with my work, on same pattern in generating report, the same error message appeared on my screen. Please help me guys, I don't have any idea in dealing with such error message, thanks in advance.
