Non Devloper trying to work on an unsupported plugin

I am using a plugin that is older and no longer supported. For the most part it works. However when I have it enabled I cant upload images using the media uploader. I get the “Are you sure you want to do this?” page. So I have been disabling the plugin, updating my post as needed then turning it back on.

I am not a developer but I can poke my way around code and understand some of the basics and structure of PHP.

The plugin has nothing to do with uploading. I dont see anything that should be causing issues. The plugin is used to post my wordpress post into a vbulletin forum I have. The posting to the forum is working fine. Its just when I have it enabled, I cant add images because the uploader breaks.

I have seen lots of plugins that cause this same error so I have been trying to find a pattern or piece of code that causes this type of issue, but I have come up blank so far.

Any ideas as to what could be breaking the uploader? Is it possibly a variable with the same name or some other issue?

I have tried enabling debug mode and got a couple of undeclared variable issues, but nothing major. I have tried using fiddler and firebug to look for anything out of the ordinary. The only thing I have really seen is the link to the media uploader is slightly different when the plug is on or not

Plugin ON

https://www.domain.com/wp-admin/media-upload.php?post_id=706&type=image&TB_iframe=1&width=640&height=808

Plugin OFF
https://www.domain.com/wp-admin/media-upload.php?post_id=707&type=image&TB_iframe=1