avatar help??

i've been trying for a while now to get a picture to show under my name, but i keep getting this page(below) telling me it can't find it. i don't know if I'm doing things right though. i upload the pic and enter the file name it gives me into the avatar url column and then hit edit profile. the dimensions are 128 x 84 pixels and 4kb in jpeg image format.
Can anyone tell me what im doing wrong because im sure its not the picture. ive tried it with a few others that ive uploaded and i get the same results over and over. i would really appreciate some help on this. thanks

this is the page that pops up before im redirected to the control panel/options section:

Warning: getimagesize(): Unable to access ats386_Three_Aliens.jpg in /home/virtual/site3/fst/var/www/html/forum/memcp.php on line 328

Warning: getimagesize(ats386_Three_Aliens.jpg): failed to open stream: No such file or directory in /home/virtual/site3/fst/var/www/html/forum/memcp.php on line 328

You have successfully edited your profile, you will now be taken back to the user control panel

you need to specify the entire path of the image.

Which in this case is www.abovetopsecret.com...

ahh. where is my dunce cap??!! thanks a lot