I have got similiar problem. I don’t know what to do :(
There you have details:
After I reach 147 categories ( including root categories / subcategories ) I can’t add more through admin panel.
I tried to delete a few of them and started adding again quite new list, but I came across the same problem.
After I have 147 categories ready and I am trying to click on “Add new” the page stops loading in:
<a href="http://mypage.com/index.php/admin/"><img src="http://www.mypage.com/skin/adminhtml/default/default/images/logo.gif" alt="Magento Logo" class="logo"/></a>
Logged in as Janusz<span class="separator">|</span>
After it stops there normally should be:
(...)21 April 2008<span class="separator">|</span>(...)
but it is not. The code is finished just after “Logged in as NICK”.
I tried different browsers and clear/off/on cache.
Thanks for your help