Whenever I try to use the toolbox(I'm using 2008m), it just appears as a white square on the side of the screen.

Also, I tried to add an image of it but it didn't allow me to post the topic when the image was included.

Update - now on 2011m and it still doesn't work.

This is because the client you are using uses a webview for the Toolbox. Clients like yours uses Internet Explorer for webviews, and Roblox doesn't support Internet Explorer. Clients this old can't even load webpages, so you better have some coding knowledge or else you an't make any kind of BrickBattle game.