Joomla! Discussion Forums

hello
Like i told you before I'm a noob.

I try to create a plugin to use it in my articles in the form {GVI|PathToMyFolder}
Till now I've got the inspiration from other plugins but i can go further because of some errors. I upload here my experimental plugin. Maybe somebody can tell me what i'm doing wrong and give me some suggestions (i prefer the code)...a link to a complete joomla codindg tutorial will be great (i know some vb )

Thanks