Making netpbm files executable

How do I make the files executable as it says in the Config please?
Aslo where do I put the folder and then the what will be the directory!!
i put it in the gallery folder with the directory Config Wizard could not find it.

Hope someone can help
Thank you

Berenice
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The following information is required to get an answer:
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL www.dailly-parish.co.uk\gallery
Gallery version: 1.5l1
Apache version: don't know
PHP version 4.3.2
Graphics Toolkit: netpbm
Operating system: window server 2003
Web browser/IE6