This was probably caused by stretching your texture. Go to Map-> Check for problems. This error should appear in Hammer as something about a the texture axis, I don't remember exactly. Delete the faulty brush and redo it, this time without messing with the texture scales.
Killer-Duck Homicidal Anatidae
2008 Mar 5 • 1169
633 ₧
As eDan says, this is usually caused by stretching(eg. extremly large scales on a brush-face). Delete and re-do all the brushes where you used the Surf_Flyzor2-texture and see if it helps.