Hello,
I am very experienced Web Developer, (8yrs).
To fix the issue within you jQuery plugin/function I have several approaches:
1. to find out has the function blocked by cookie issue, to clear all browser cache and test
2. Is the function in a conflict within the jQuery cookie plugin itself
3. Might be some function/variable names are override.
Although the above, I would like to hear you and get more informations from you, so we can fix this in minutes, very quick, and push your project forward to touch the horizons it dreamed off.