Avast mistakingly Finding VB programs a trojan

Why is avast suddenly finding programs written in visual basics as a trojan?? ie: YaZak Pro chat client … which i have used for years and know the person that developes the program, and know for a fact that it is not a trojan. Also finding other safe programs as trojans.

To know if a file is a false positive, please submit it to VirusTotal and let us know the result. If it is indeed a false positive, send it in a password protected zip to virus@avast.com
Please, mention in the body of the message why you think it is a false positive and the password used. Thanks.
Other possibility is JOTTI. VirusTotal and Jotti both have file size limit of 10Mb.

As a workaround, you can add these files to the Standard Shield provider (on-access scanning) exclusion list.
Left click the ‘a’ blue icon, click on the provider icon at left and then Customize. Go to Advanced tab and click on Add button…
You can use wildcards like * and ?. But be carefull, you should ‘exclude’ that many files that let your system in danger.