I got all the map pieces, the orcish document, the sword, destroyed the weapons in the cave, repeatedly wandered from Phexcaer to Hermit's Lake, but I cannot get to the orc army and win the game! Someone please help me with this infuriating fucking bug.

Never mind, I realized that my characters had just examined the orc document; once I found one with a high level of reading and had him look at it, I was able to beat the game. I did it at level three.