This type of thing comes under what I call Strange, Odd and Curious Behavior, and usually translates into corruption, in one form or another.
Was the file transferred to machine that had Access 2010 installed, or was Access upgraded to 2010 on the machine that originally held the file? If the former, how was the file transferred to the new machine, i.e. what media was used? Flash drives/thumb drives are notorious for causing corruption when transferring Access files.
The first thing to attempt, if you have the original file, is to recopy to the current machine. If not, create a new, blank file and import everything into it. Only takes a minute or two to create and check out, and if it doesn't work you haven't really lost anything! And, amazingly, it does frequently work when Strange, Odd and Curious Behavior occurs!
Linq ;0)>
The problem with making anything foolproof...is that fools are so darn ingenious!
All posts/responses based on Access 2003/2007