Auto-Import Broken

Hey all, been using Idea for a couple years now and loving it. Running on Ubuntu 7.10 with JDK 1.6.0_04.

Unfortunately, Idea has recently stopped automatically recognizing even common classnames to import. For instance, if I start up and create a new project from scratch, "List" doesn't automatically get imported, and hitting Ctrl-Enter doesn't bring up any options. Organizing Imports also has no effect.

The catalyst for this problem seems to be that I recently created a new project B that relies on some common modules from project A. The modules relied on project libraries like Spring 2.0.7, etc that were stored in the Project. I wanted project B to use the new version of Spring, so I added the modules as a dependency, and created project libraries with the same generic name "Spring" that actually contained the Spring 2.5.1 jars. This links fine and works when deployed, but I think something caused Intellij to get confused. The libraries get imported correctly if I copy source containing the classname from a different file that has the library imported. Also, if I manually enter the import statement, it works fine.

Relevant settings:
Insert Imports: "Ask"
Show Import popup: checked
Use single class import: checked
Insert imports for inner classes: not checked
Optimize imports on the fly: checked
Add unambiguous imports on the fly: checked

Possible ideas?
1) JDK problem?
2) some global classpath issue in IntelliJ? I have no global libraries specified...
3) a setting that I'm not seeing somewhere?

Any ideas? Thanks in advance, this is driving me batty.