Iuri, for completeness:
Verify that the file permissions are consistent with other xql files that are working.
Sometimes an xql file will not load, for example if there is an error in the form of the file.
Remove any tabs in the xql file. xql files do not like tabs. Results can seem unpredictable. Also check for other problematic invisible characters.
Check for the existence of the query name used elsewhere in the xql file or another xql file in the same directory.
I've been frustrated with nonpredictable xql problems. Most have been caused by one of these.
Hope this helps,
Torben