HTMLUnknownElement

hi , i am getting a some response from a query , and created a .xml file with response. and trying to load my grid from that file . and i got below exception .
GET localhost:8080/MyPortal/forms/%5 … Element%5D
404 Not Found 12ms dhtmlxcommon.js (line 15) HeadersResponseHTML

any ideas why i got such exception.??

Please be sure that url in the load command is correct

thank you. it was issue with special characters like &, > < , ’ and " . so i handled it . now the issues .resolved.