Ok for the first part make sure you are using the correct UBB tags in front and rear of the link...also if I remember correctly there was something about the link that had to be adjusted (but I am rusty to be honest).

For the second.... there is a folder for user avatars in the UBB directories.. you just have to allow users to upload their own avatars in the Control Panel (and make sure that the folder is read/write enabled).

Short answer..if you need a more detailed one, I will write it out in a bit when I get home from work.