[GeoNetwork-devel] Error in advanced search

Hi list. I am using Geonetwork 2.2. I have a metadata record with this extent:

North: 37.00194 South: 36.96027 West: -6.01982 East: -5.93648

I put at the textboxes around the map this numbers:

North: 38 South: 36 West: -7 East: -5

And the search returns this record. Perfect.
When I change this parameters and put for example this:

North: 37.9 South: 36 West: -7 East: -5

It not returns nothing.
Where is the problem?
Making csw queries has same problem.
Anybody knows how to fix this?
Thanks.