I always try to present a popover from a cell inside a tableView this way:
[myPopover presentPopoverFromRect:cell.frame inView:self.tableView permittedArrowD
The cell frame is going to be something like 0,0,width,size, i dont believe it will have its X and Y relative to the tableView...you want to use - (CGRect)rectForRowAtIndexPath:(NSIndexPath *)indexPath for this, this should return you the correct frame for the cell relative to the tableView...here is a link UITAbleView ref