Troubleshooting Clutch/Shifting issue?

[mgfranz]

So... I was driving back from the coast today, nice drive at 80+/-, never had a problem shifting before, coming to my exit I tried to shift from 5th to 3rd, except the gear would not disengage. Engine died at the light, I shoved the shifter into 2nd and started the car and drove it to the parking lot...

So basically, I can force the gear box into gear and drive the car but I am unable to shift, the pedal is not soft or spongy, it depresses and releases as it always had, only I cannot place the shifter into any gear with the engine running. So... I'm thinking the clutch is fine and the problem is somewhere in the hydraulics which isn't allowing the clutch to disengage. Fluid level is full, no leaks anywhere. Since I do not have a service or Bentley manual, and my friendly Google search is not helping in troubleshooting this issue, I was hoping for some input from the best.

2001 Boxster, 86,400 miles