If your normal drop-down (a.k.a select-type) attributes stop working after installing my Attribute Image Swatch plugin, then your site’s been the victim of an improperly-coded plugin’s installation SQL script. This issue has been “known” for a couple of years, with swguy posting this in April of 2012.
I’ll be updating AIS real-soon-now to pro-actively re-insert the missing configuration items if they are not found in your store’s database. The base Zen Cart install started, as of ZC 1.5.3, creating the problematic configuration items as hidden items within the “Modules” configuration group to circumvent problems in the future.
Update (2015-03-16): Attribute Image Swatch v1.1.4 has been released, including the above change.