Lincoln,
The SHC68-68-EP is design to fit in a Daqcard that is in the bottom PCMCIA slot, and the PSHR68-68 (is the strain relief right?) does not has any limitation about space... so if you use the PSHR68-68 cable in the top slot and the SHC68-68-EP in the bottom slot you will work fine. I already check them here.
Good luck!..
Nestor Sanchez
Applications Engineer
National Instruments
Nestor