Why is there a completely losing move in my engine's opening book?

Originally posted by Marc Benford
After 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. e3 Bf5 6. Ne5 Nbd7
(Slav Defense - Chameleon/Chebanenko Variation)
My engine's opening book continues with the losing 7. g4??
And then it continues with the variation 7... Nxe5 8. dxe5 Nxg4 9. cxd5 Nxe5?!

I've made Houdini 3 Pro evaluate the position, and indead 7. g4?? is completely losing.
Houdin ...[text shortened]... utes, so maybe there's some deep hidden secrets in the move 7. g4, but it looks very unlikely...

The moves in that line was supposed to be ...
1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. e3 Bf5 6. Ne5 e6? 7. g4!