When I implement a Virtex-4 MGT design, the following warning is issued by MAP against RocketIO TX serial pins:
"WARNING:PhysDesignRules:367 - The signal <DESIGN_MODULE/TXN> is incomplete."
The signal does not drive any load pins in the design.
If all signals are completely routed at PAR, this warning can be safely ignored.
This issue is being investigated for a fix in a future release.