Help! Upgraded modem with firmware, now Thunderbird and mailwasher won't work!

[crankypants]

Hi, I just upgraded my Bigpond ADSL to ADSL+2. I have a Siemens speedstream 4200 router which I made compatible with the ADSL+2 by downloading some firmware for it. Everything is working fine except now Mailwasher Pro and Thunderbird get errors when trying to access my mail. I can view my mail online with bigpond, but can't figure out why I can no longer use my programs to get my mail. Mailwasher tells me: The POP sever is not responding appropriately, make sure you have specified the address of a POP server.
Thunderbird tells me: An error occurred with the POP3 mail server. Mail.bigpond.com responded: then it's blank.
I can still send email from Thunderbird, and I've noticed that each time I open one of these programs that AVG antivirus email scanner comes up, which says: AutoPOP3: connecting to: then it has an IP address. I've tried to look up the address and apparently it doesn't exist??
If anyone has any idea at all what is going on, it would be greatly appreciated, I'm not very technically-minded......I have XP SP2 by the way......hope someone can help Thanks

[patio]

In ThunderBird right clik your Account andd select Properties then server settings...
Write down what it says under POP3 and check it against what your ISP's settings should be.
The SMTP settings are fine if you are able to send mail so no need to check those.

Do this for all accounts you are having incoming troubles with.

[crankypants]

Thanks for your reply. I've checked those settings and it has made no difference, I still get the same errors. I've tried reinstalling and turning off my antivirus too, and nothing has worked......Any other suggestions? Thanks again...

[crankypants]

I've worked out what the problem was (after calling tech support for bigpond who were no help and blamed it on my antivirus). It was the firewall setting in my router, the connection to my mail was timing out, so I've turned it off. I've never had an issue with having the firewall on in my router before, so I don't really understand the 'why's' of it, but it solved the issue. Thank you for taking the time to reply patio

[patio]

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