Debugging Rs.MoveFirst and rs.movelast errors

[Caro]

I do a Rs.Movelast if I'm at EOF and rs.MoveFirst at BOF. Sometimes this works and sometimes i get an error saying the action was cancelled by an associated object. I can see my recordcount and there are records present (usually about 2 or 3 in each recordset). What else can I look at to get a clue why this sometimes works and sometimes not??