Hi,

I have also had misterious problemes with parallel port: it was the PIC
programming device of Bojan Dobaj. I found out that the bit #5 (mask:
0x20) should be zero in the appropriate control register (normally it is
the 0x37A). I guess it controls the bi-directional characteristic of that
printer port. If this bit high, one can not control the data register as
output.
I hope it helps.

Imre