Check the documentation of that aČ scanner:
aČ Malware-Info: Riskware
Programs detected in the Riskware category are not directly malicious, but are often used in conjunction with Malware. This is why the a-squared scanner detects them too.
Programs which are classified as Riskware can be:
* IRC chat clients
* SMTP clients
* Commercial downloaders
* Commercial monitoring tools
* Proxy servers
* Password recovery tools
* Commercial remote control tools
* FTP servers
* Telnet servers
* Other tools which are built to kill processes, hide windows or read system internals automatically.
If you don't want Riskware to be detected by the scanner, please uncheck the checkbox "Scan for Riskware" at the scanner screen.
If you download mIRC from www.mirc.com
and nowhere else, you can ignore this message. The riskware classification is some overzealous warning that this program can sometimes be used in malicious ways. If counting to 50 was malicious, Calculator would be Riskware.