We had a problem with 'Invalid Seek Offset' error occuring randomly at the same command, which was a Create Cursor command, creating a fixed cursor of table structures. This problem occured at our client's site. We could not reproduce it at our office. Microsoft's response to this problem was that this error is an indication of a 'Memory Problem'. They suspected it was the result of 'junk coming off the swap file'. Their suggestion was to set the buffer size to 256 using the SYS(3050) command. (This is the default value.) They also suggested turning virtual memory off, from the Windows control panel. We never really solved the problem. Our work-around was to create a DBF rather than a cursor, since ours was a very small table.