ok, so i did what you said and still was having issues, so i decided to run the module's files through coder (drupal.org/project/coder) and it found a couple of errors (mainly just little picky formatting things), but once i fixed those i no longer get white screens all over the place!!! (the main issue it found was on line 189 of uc_cano.module where array key oid wasn't in quotes (use ['oid'] instead of [oid])). so yay!!...

...kind of..i still have 2 issues:
- it doesn't work with uc_aac (Ajax Attribute Calculation). when you choose the option that the dependent attributes are NOT associated with, they fade out like it's going to work, but then they are called back up...not sure what to do here but disable uc_aac for the time being because the CANO aspect is more useful to me on this site
- maybe i'm misunderstanding the logic behind the cano definitions admin page, but what i had to do (besides disable uc_aac) was to choose the option i DON'T want the attributes to be linked to for it to work as desired...basically it seems to me to work backwards.

explanation:
i have an attribute for these letters of "ribbon" with options "no ribbon" or "add ribbon". it seemed to me that the logical thing to do would be make "ribbon style" and "ribbon type" dependent on the "add ribbon" option, so that's how i initially set it up, but it only displayed those attributes when i chose "no ribbon". so contrary to my logic, i set the "ribbon style" and "ribbon type" to be dependent on "no ribbon" and it works as i would have expected with it being dependent on "add ribbon" option. does that make sense? as long as i set up the attribute to depend on the attribute option i DON'T want to associate them with, it works. see http://www.alabamarecycling.org/letter-creations/options/colors/test2 for an example and screenshot attached of CANO definitions (this is just a dev site).

all that said, this is a great, and VERY useful module and i salute you for doing such good work thus far. maybe it's just my install or my use case that's the problem (or just me for that matter!), but it's a great module, so props! you saved my butt on this one. if you can help explain about how it's setup and/or help it play well with uc_aac (another very cool module), that'd be awesome. let me know if you'd rather i create a separate issue for those.