Need more understanding for jQuery - HEEEELP PLS!!!

Need more understanding for jQuery - HEEEELP PLS!!!

Hi all! i am new here and im happy for this place. there cant be enough help out there

i have some problems to understand syntax and function of some jQuery stuff:

I have a little tool to find a username in a database. If the name is still free the code should show a green box with a link in it. The link should open a thickbox with a formular inside.

this is the part where i generate a link:
$("#msgbox").fadeTo(200,0.1,function()  //start fading the messagebox
         {
           // Here i generate the Link to open the thickbox, but its not working... why is the thickbox not showing up???
           $(this).html('Domain ist frei <br /> <a href="test.php?height=200&width=300" class="thickbox" title="">Neuer Kunde</a></p>').addClass('messageboxok').fadeTo(900,1);   
         });



Why isnt it working? The thickbox isnt showing up. I only see the normal Html-page where the link goes to. if i first start the same link without generate it with javascript it works perfectly well.

whuzz happening here?

thx in advance,

koala