@Anidarc: It looks like xAmorphous is from the
Community Pack. Didn't realize that when I put it in; from the generic-looking thing ID I probably assumed it was from vanilla HL. So for the short term your solution is to install that pack (which, believe me, you want anyway on account of all the cool stuff that's in it!). Longer term, I'll be updating the Enhancer's Handbook to replace that version of Amorphous with one of my own.