ms_newShapefileObj gives error in mapserver 4.4.2

[Joukje]

Hi list,

I have a problem with opening a shapefile in php/mapscript since we started
using mapserver 4.4.2. (php 4.1.2) instead of 4.0.1 (php 4.3.11).

The following line of php now returns an error:

$objShapefile = ms_newShapefileObj("gspplan/bespreek", -2);

-->
Warning: [MapServer Error]: msSHPOpenFile(): (gspplan/bespreek)
in /project/gspvg/wwwontw/page/object_attributes_edit.phtml on line 80

Fatal error: Failed to open shapefile gspplan/bespreek
in /project/gspvg/wwwontw/page/object_attributes_edit.phtml on line 80
--

I also tried opening the shapefile with the full pathname, but the same
error occurred. Does anyone have an idea what the causes this problem?

Thanks!

Joukje