Jailbreakme not working on 4.0.1

So recently I was given an iphone, but I have t-mobile so it needs to be jailbroken. Its a 3g and has FW 4.1 on it. I ended up downgrading from 4.1 to 4.0.1, because with the use of tiny umbrella, I found that the 4.0.1 SHSH files were saved. Long story short, I was able to downgrade and currently have 4.0.1 FW on the iphone. Whenever I go to jailbreakme.com it recognizes that my phone can be jailbroken and allows me to slide the bar. Once i slide the bar everything goes away and it sits there on the purple screen. I cleared my cache, history,and cookies, and restarted my phone, but the same thing happens.
Can anyone help me with this????

 

ok I gotcha. I went back to 4.1. If I were to just go ahead and jailbreak, could I then later update ultrasn0w and unlock my baseband when the new unlock comes out? Also, say this was possible what jailbreak would be best to use?
Thanks.

 

ok great! Thanks. I jailbroke the phone, but something I have noticed is that even before cydia was installed, 3g does not seem to run very well with 4.1. Would it be possible to us pwnagetool to create a custom 3.1.3 FW? I don't have the SHSH blobs saved for 3.1.3, but I don't know id that matters or not.
Thanks