coming to Canada for a short visit..any problem?

If you have definitely spent more than 730 days in Canada since receiving PR in November 2007 (which the timeline you post suggests you have), and you have possession of your PR card valid until November 2012, why would you think you might have any entry issues coming to Canada for a short trip? Actually, until November of this year, even if you had only spent a few days in Canada so far, you should have no residency obligation issues since there will still be enough time to have spent 730 days in Canada prior to November 2012.

I don't see what complication you are referring to.

The better you can positively state (and better yet, document) the actual dates you were in Canada, the stronger your case is IF they were to conduct a residency interview . . . but with two years remaining on your PR card it is very unlikely they would conduct a residency interview.

If you have spent 650 days in Canada so far, you only have to be in Canada 80 more days between now and the fifth anniversary of your landing . . . technically, even if you did not return to Canada until July 2012 there should not be a residency problem. The more time you spend in Canada (and keep records of the time) the less likely you would even be examined about residency, let alone have an issue if you were.

If meeting the residency requirement is of concern to you, compile what documentation you can for past dates in Canada and from here on maintain good records to show dates in Canada; the more detailed (precise) and accurate your records of time in Canada and travel or residence outside Canada the better . . . assuming, of course, you remain in compliance with the residency requirement (which is so liberal that if you really want to be a permanent resident of Canada there should be no problem complying)

By the way: Technically you are not eligible for a visitor's visa (since you are a PR) and probably would have to make misrepresentations in an application in order to obtain one (I am not familiar with the application form itself . . . but I am pretty sure that one way or another you would be required to give some information that illuminated your PR status, in which case the app for a visitor visa should be denied as a PR does not qualify for one). I am familiar with the fact that many PRs who have indeed breached their residency obligation apply for various types of visas just to obtain entry into Canada (rather than applying for a TD, which would trigger the residency evaluation with predictable results), oft times student visas, but visitor visas as well, and once they have gained entry into Canada they stay for two years in order to meet the residency requirement and keep their PR status intact. Similarly (though I've seen fewer reports of this), some PRs within their first five years but who have been outside Canada for so long (over three years total) that they cannot meet the residency obligation, apparently also employ this tactic to avoid a residency evaluation when seeking entry into Canada . . . again for the purpose of once in Canada staying long enough to meet the residency obligation and keep their PR status intact. However, again, I am pretty sure that one has to at least make a material omission if not some overt misrepresentation in the application for either a student or visitor visa in order to obtain one (again, since PRs are not eligible for either), and making misrepresentations to obtain entry into Canada is one of the things that can render a PR inadmissible and thus lead to the revocation/termination of PR status. Just a heads up.