... but your query looks similar to automated requests from a computer virus or spyware application. To protect our users, we can't process your request right now.
When asked about this in the forums in the past, Blogger has described it as a problem with "fuzzy detection". Like many chronic Blogger problems, it doesn't have a simple solution.
Google, like every large Internet presence on the face of the earth, is constantly under attack. If the bad guys use a large and varied army of botted computers, the Google attack detection servers have to look for a pattern in the attack. In some cases, they will see an attack coming from a block of Internet addresses. You may be unlucky enough to have your connectivity using an address similar to the block detected in the attack, and the fuzzy logic will see your address as part of the attack.
If you seem to be affected by this detection more often, that may not be your imagination. Internet advertising being what it is, a certain type of Internet customers are attracted to certain ISPs. A large ISP, with customers more interested in high bandwidth and file sharing, will provide good targets for the bad guys. The bad guys use can file sharing to hack their victims computers, giving them lots of new botted computers, which they can then use to launch their attacks against Google and other corporations.
If you are using the same Internet service as your neighbours (maybe not those geographically near you), even though you may not do file sharing so intently, and you may keep your computer clean, you may still be seen as a possible attack vector by Google, simply because you are part of the same address block as a detected botnet which may be actively in use.
When you see this error on your screen, you could consider this a wakeup call, and seek reliable and professional help, like DSLR Forums - Security Cleanup - if you're at all uncertain about the status of your computer. The advice provided at Security Cleanup is free, but the helpers there are carefully moderated, and they are very professional and respectful to those asking for help. Observe the *Mandatory Steps Before Requesting Assistance*, and you'll be starting properly there.
Also, remember that, unless your readers are very homogenous in their Internet access and use, even though you see this error, it's not a given fact that this error is affecting access to your blog, specifically. This error appears to have an affinity based upon Internet access, not upon Internet content.