I am not an expert here, but I have seen exactly this problem. Look for a thread called "MC case sensitivity and sub-packages" from January 2010. My recollection is that the only way to get around this mix of case sensitivity is to delete the offending package and add it back with the required case. I *think* you can delete by "delete working copy" and not clobber your code - I THINK. It get even weirder with methods added to a package; there it appears that any *pAckAGeNAme variation on case will assign the method to the package.

From: pharo-project-bounces@lists.gforge.inria.fr [mailto:pharo-project-bounces@lists.gforge.inria.fr] On Behalf Of Max Leske
Sent: Monday, November 15, 2010 5:53 PM
To: pharo-project@lists.gforge.inria.fr
Subject: [Pharo-project] Monticello package names

First of all, I couldn't figure out how to actually remove a package from Monticello. Unloading it simply emptied it but it would still show up in the list. Would be nice to have that.

Now to the actual problem: suppose I have a package named 'FooBar'. Now I want to rename that package to 'Foobar'. I encountered the following things while trying to do this:

creating a new package 'Foobar' does nothing. The old package stays in the list but I get no notification about what went wrong.
trying to load the old package with the new name from Sqeuaksource through Gofer fails: Gofer new squeaksource: 'TheFoo'; package: 'Foobar'. I think this is the correct behaviour.
creating a new package named 'Foobar' in a fresh image (so that the old package is not loaded in Monticello) and trying to save it to Squeaksource results in a notification telling me that the package I want to create already exists (it's messing it up with the old package).