Just going off what you say, it sounds to me like the clutch is not engaging, ie. throwout bearing not "throwing", clutch cable too loose or broken, etc.  Or the clutch is worn.  Maybe Zen can answer this.

I had the same problem (of sorts) with my Westy.  Only it wouldn't go into any gear until the engine warmed up.  Still don't know what was causing that, except I think that was around the time that the shift rod bushing right in front of the transmission fell apart on Hwy. 64 by the Ocoee river.   ::

Do you have a lot of freeplay in the pedal?  If you have too much, the clutch won't relase completely.  It will cause the symptoms you described.  The pedal should move without much resistance for only about an inch, then you should get a definite increase in resistance.  There is a wing nut on the end of the clutch cable (where it passs through the throwout lever on the driver's side of the transmission bellhousing). . . tighten it to decrease the freeplay.

As a update, I guess, got lucky, what ever the problem, it fixed itself. Maybe just stuck after 15 years, but it started shifting and has been very smooth..
Ron