Ok, now I've tried this quick and dirty solution:
Added my own array with extensions in filepost.php, and if the original way didnt work, check my array
$arr_xl=array(".xls",".xlsx");
if (in_array(strtolower(GetExtension($filename)),$Filter_Array) || in_array(strtolower(GetExtension($filename)),$arr_xl))
Still not possible to upload excel files :(
Error:
application/vnd.ms-excelee
File format not allowed! Please contact site administrator.
can this be a MIME error?
/Bix