warxSome anti-viruses can be too much paranoid about adult sites, so they can block them.
And it's true if you are visiting adult sites you need a good security system due some of them can hack your computer (sure not our sites

)
The best and true checker for malware at websites are Google
The hyperlink is visible to registered members only! If you search the website at the search by the address and the site is hacked or setup hacked code to your PC the Google will show the warning message.
Also I can suggest to you try the NOD32 antivirus. It's free to try, cheap to use, very fast, secured and very adequate for the web.