YPOPs and Avast Problem Help

Hi,
Iam new to this forum. Iam using Avast for around 2 years.
I use Office outlook 2007. Recently I installed with YPOPs to acces my Yahoo mails.
System Info:
Windows XP, AVast V4.8, YPOPs with 127.0.0.1 /localhost , POP3 :110, SMTP: 25
Iam able to send mails from my outlook but Iam unable to recieve mails.
when I start YPOPs I recieve the following message

Unable to create SMTP sever socket. Please ensurre that another copy of this program is not running.
If you are using an antivirus program withemail scanning enabled,you might have to change the port in YPOPs to a non-standard port and then make the appropriate change in your email application.YPOPs will not service any requests from your email application till you make the necessary changes.

My friend has the same configuration as mine but without Avast he can recieve the yahoo mails.

Can anyone help me?

;D