Packages install permissions needed?

[ExXeL]

What should I do when i'm installing the package my forum and the forum want FTP details because need permissions?
I'm running the forum from localhost (VPS).
How can I change that permissions without FTP or how can I get FTP details to change automatically by the forum?

[Arantor]

You need to change the files so that they are writable by the user who runs PHP, which depending on your server setup could be www-data or apache2.