Thanks shashir, Franklin. I normally would download the source or binaries directly from mozilla.org but thought I'd try out the new 1.7.5 Mozilla in package from Slackware's site. I should have listened to my initial gut feeling of "downloading this Mozilla in package form is probably a bad idea". Oh well, live and learn -- right?
I only have one other problems now, both the fonts in Mozilla and my java plugin are now broken. I guess I'll live with ugly Mozilla fonts and no java for a while, as I don't have the energy to research the problems at the moment.
Thanks again!