Current version of PHP 4.0.5

Doing the default HTTP post uploads right from the documentation I am seeing a problem where if I upload a text file, word document it works fine and reports the file size back. 
Array ( [userfile] => Array ( [name] => Computer Features.htm [type] => text/html [tmp_name] => /var/tmp//php015005 [size] => 1350 ) ) 

Array ( [userfile] => Array ( [name] => catmatrix.jpg [type] => image/pjpeg [tmp_name] => /var/tmp//php015005 [size] => 27094 ) ) 

When doing .pdf, .exe .wab (other's im not sure of)

Array ( [userfile] => Array ( [name] => ClientReferenceJS13.pdf [type] => application/pdf [tmp_name] => none [size] => 0 ) ) 
Array ( [userfile] => Array ( [name] => dMC-r3.exe [type] => application/octet-stream [tmp_name] => none [size] => 0 ) ) 

There not being uploaded althought it seems they are by the httpd processing spinning up.

Any ideas what would cause this?

L