ebay will not allow me to choose a category to list an item.it just keeps saying please choose a category . when i do it just repeats

If you have never listed in the category or if you listed but didn't have a successful sale.  It's ebay.  All you need do is contact them and tell them you want to sell one item in that category and you'd like them to allow it.  They generally will.  When I recently started selling here in ebay they asked me what categories.  Of which I have several.  I told them but had a category later I wasn't selling in and wanted to.  They let me list one and it didn't sell.  When I went to list a second one the same thing happened to me.  So I called and they allowed me to do a few listings.  They want to establish a successful sale before fully opening up a new category.  So call them.  I know pain in the butt but thats the way it works.

As noted, when choosing a category you have to follow the trail all the way to the end of the hierarchy of options. If that doesn't work, then one workaround is to go to any listing in your chosen category, and click on the "Sell it yourself" link that appears below the Gallery image on the listing page. It will bring up a new listing form, with the category (and listing title) already filled in.