RootFolder Query string bug

Scenario:
Funny, still finding weird bugs in SP2007.

I had a navigation web part and had a link to add a new item inside a sub folder within a list.

When I click on link I can add new items but when I hit OK to save it, I gets Access Denied.

But if same account directly navigate to the folder with in that list, he can add a new item without any issue. hmmm...

Solution:
I copied both the Urls ( New item page link ) and started comparing.

Sample:

Working : http://localhost/Lists/Custom/NewForm.aspx?RootFolder=/ABC

Not working : http://localhost/Lists/Custom/NewForm.aspx?RootFolder=/abc

Lesson learnt:
Urls are not case sensitive but Query parameters are ( specially if they are not handled for ignoring case )

Changing the abc to ABC solved the issue.