CouchDB chokes on malformed URLs. This request works in Firefox but not curl or when called from a PHP script. The problem is that the space after the comma in the endkey is not properly encoded. The solution is to remove the space.

localhost:5984/db/_design/forum/_view/postsbak?startkey=[“forum/test_page_1”]&endkey=[“forum/test_page_1”, {}]

Luckily the CouchDB team know about this (Doesn't gracefully handle malformed URLs) and hopefully will be fixing it soon.