Are you behind a harsh and unforgiving peice-o-crap firewall like norton security ?
Or even zonealarm ( a good one ) with setting that are too high ?
asses you security software and try to eliminate that variable as PB needs to have a port open for the updates.
This has caused many gaming problems with PB.
vista also creates about 50 more variables to deal with than earlier OS, and naturally will require more work. Check vista security settings to see if its preventing the PB update.

Did you manually place the  file into the PB direc tory in your 2142 game?
If not you havent done the manual update yet.
Do it.
reboot is mandatory after dropping the file.
Heres the procedure ( including the goods ) for the most current manual update.

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the file itself is here ( dont clik on it ) Right click on link and "save target as" following their instructions below      http://www.evenbalance.com/downloads/bf2142/pbsecsv.htm   g

   "To Manually update your local PunkBuster Security Files, choose "Save Target As" ,and explore to find your game folder and the subfolder called "pb", then save this file in that location (/pb/pbsec.htm or /pb/pbsecsv.htm). The next time you start your game, your PunkBuster will have the latest security information necessary to accept auto-updates from PB Servers. "
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---- text info for editing htm file manualy if even that doesnt work, cut and paste these characters below into the pbsecsv.htm or the pbsec.htm file, replacing whats in it now,.
----------------------------------------------------

S 3 MASTER6.EVENBALANCE.COM 17567 0

S 4 MASTER7.EVENBALANCE.COM 17567 0

S 5 MASTER8.EVENBALANCE.COM 17567 0

S 2 BF21421.EVENBALANCE.COM 17567 0

M BF21422.EVENBALANCE.COM 17567

F A K 1375 4560 54A63DA063851D157CF94589582F563C 7388AA9234E039A5840D11E99DE9A5D6

F C K 2057 711F0 260E9D3391F5717009A885ED96237F93 15CA2C971A8EFF24393A767AE49851DB

F S K 1669 D7350 162CFB0B420C49381FF2F12D9CA0FB6B F04C815579E86E6195DA64AAF3038898

F A M 1375 11 74DF4244ADCD334C1C7A77D0142D4F2D 9ACCA9C508F42331DA7077343A9C92A4

F C M 2057 11 74DF4244ADCD334C1C7A77D0142D4F2D 9ACCA9C508F42331DA7077343A9C92A4

F S M 1669 11 74DF4244ADCD334C1C7A77D0142D4F2D 9ACCA9C508F42331DA7077343A9C92A4

F A W 1375 F000 98EE1FB02A119BF7B5F4B0EB22CE2A2D 82D0FFB2BA4B373A5613AA12E22CFE27

F C W 2057 C9000 61BE291FC43BCD40C51F80F458DD6F43 1212DB50C02856AEC9A6871118D80165

F S W 1669 86000 1B7BAFA36FA4112F165D90FBB1639E0C AD8B06EF5B753A9E28F0B47152DD5DF8

F A L 1375 7BB0 EFFA10DEC6D8142E3371FC3E78F9C277 1C5B404397D585AFC4D8A6FD376F37C4

F C L 2057 D87A4 8E29A51BE00DC73D1FFD4F06FE8891AD 35A49B96D7EE271742C368B3BE719704

F S L 1669 16BFC4 26220C68DA401A46EECF60BCE1B0811A 4AC187D8CF3270401AE763467EB4EA47