Mapserver: “Premature end of script headers: mapserv,”

Some of requests to the Mapserver return “Internal server error”. When I checked the Apache log I saw that there are several error messages:

GDAL: In GDALDestroy - unloading GDAL shared library., referer: http://...
GDAL: In GDALDestroy - unloading GDAL shared library., referer: http://...
Premature end of script headers: mapserv, referer: http://...

I’m not familiar with the GDAL and I’m not sure how to fix the problem.

Update

Ubuntu 13.04
GDAL 1.9.0, released 2011/12/29
Mapaserver 6.2.1
POSTGIS="1.5.3" 
GEOS="3.3.8-CAPI-1.7.8"

The “Premature headers end” resolves in not loading some part of the map, but not the entire map. The strangest think is that when I zoom in some of the missing parts are getting shown.

Update 2:

Here is another error I found:

msProjectRect(): some points failed to reproject, doing internal sampling.