manageCategories.asp problem loading

Recently our manageCategories.asp in the Control Panel stopped loading. There is no wait while it loads, it just immediately breaks. What is displayed is parts of the page or code after the section that lists the categories. Anything before the list never appears in the browser or even the page source.

I fixed that by removing the the images for Hidden and the Globe to view the category. This is probably only a temporary fix. We nearly have 3000 categories so my best guess is that it isn't an asp error it is just that we are just overburdening the javascript that is creating the expanding list. I don't have much knowledge of javascript, and really don't think this is a bug so I am a bit hesitant to open a ticket for it. Is there anyway to permanently fix this?

The reason we have so many categories is because we have 25,000 items and a design Gallery on top of that. We use categories for the gallery to be able to add the parts to the project and allow our customers to order them on one convenient page. We are looking to lessen our amount of categories where we can but nothing that will cause a drastic reduction.