Help with error message. What in the world??

Hello, I am trying to write a program that the allows the user to select the segment and offset of a memory location and display 32 bits of the memory there. I put together some code and assembled and linked it. it allows the user to enter the segment and offset, but then it says:
FCB unavailable
abort, fail?

what does this mean? I would appreciate any help, I can post my code if anyone is interested (i doubt it)

thanks