It sounds like a record locking situation. But I bet if you made an Execute SQL call and the looped through the results to import, you could work around this limitation.
It is a record locking problem, exactly; I've not played with Execute SQL calls before; looks like I have some serious homework ahead of me. Thanks!
FM will read a locked record for importing, it just won't let you make any changes to the record. Try to make sure you are directy importing or Loop through and make a variable array copying the info and switch to the new layout and import the records.