Invalid nib registered for identifier ((null)) - nib must contain exactly one top level

I'm using a custom UITableViewCell. When I try to run my code, I got this exception stack and I can't understand the source of the problem:

terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'invalid nib registered for identifier ((null)) - nib must contain exactly one top level object which must be a UITableViewCell instance'

Please note I am not using Storyboard.

EDIT:

This is my relevant code which cause the problem according to the breakpoint:

[tableviewSupport registerNib:[UINib nibWithNibName:@"HotelCell" bundle:[NSBundle mainBundle]] forCellReuseIdentifier:CustomCellCId];