cannot join public server

[gskitzod]

i have been playing ut for quite a while and just now i have had the message

ANTI TCC HAS FORCIBLY REMOVED U FROM THE GAME

the server could not verify the file SPIDERSTEROIDS.U

this message is displayed because an important file could not be found or a non optional package is not loaded.
please contact the server admin if u think the file or package SPIDERSTEROIDS.U should be optional

ANTI TCC V1.17 BUILD 2004 7 22 1745

I CAN JOIN OTHER SERVERS but cannot join this particular one is it me the client or the server pls advise

many thx for help and im sure iv seen this b4 but dont know were and im due a 2v2 at 3.00 pm gmt

thx in advance

gskitzo