Bob
Just to make sure I understand your problem correctly, you've got an existing portal indexed with a set of tabId's that no longer match the new install, because the new install is on a different installation.
so, indexed and 'out there' are URls that look like this:
domain.com/mypage/tabid/66/default.aspx
and the relevant, new version of that page is this:
domain.com/mypage/tabid/123/default.aspx
If that is correct, then I can help you out without having to delve into all sorts of regexes and other things.
With the Url Master module, you can set up any url to be used with any DNN page. That url can either just show the page (a 200 status) or it can redirect that page.
So, using the above example, all you need to do with the Url Master module is go into the 'admin->page urls' page. Select the 'mypage' page in the left hand side list. Then, add a new Url, and type into the Url box : /mypage/tabid/66/default -select '301' as the http status type - then click on 'apply changes'.
Now try out your 'old' url. It should issue a 301 redirect to your 'new' url. Note that it shoudl also redirect to the human friendly version 'mypage.aspx' rather than mypage/tabid/123/default.aspx
Any other questions, let me know. You can also start up a thread on the support forum at http://www.ifinity.com.au/PRoducts/Support_Forums/
-Bruce