I purchased lattice c compiler about a year or so ago, it was version 5.0.1
and I haven't been notified of any upgrades, but I see patches to bring 5.1
to 5.1a and 5.1b, whats up wit dat!
A number of the addresses that Lattice passed on down to SAS weren't in the
best of shape and a number of letters get returned (I know, I saw the huge
pile when I worked there). You probably want to pop a note to them asking
what's going on. I have never heard of 5.0.1, we only used even numbers
previously for production releases. If you have 5.10 then you can just use
the patches here, if you have 5.0, you will have to purchase the upgrade
from them directly. I do not work for them anymore so I really can't help
you in that respect.