It'd be the PM recipients who'd need to run that, not me. :p
I did some testing and have confirmed that the filters feature in WinHTTrack is sufficient to control its navigation in a logged in session, making the tool viable for grabbing PMs. Which is a very good thing as it is more than just logout--there are other kinds of links like "delete" that could potentially do other unwanted stuff.
I'll admit that the steps are not easy for computer novices unfortunately, partly due to having to deal with cookies in order for WinHTTrack to make use of your active login session. If you don't have too many PMs that need transfer (keeping in mind that everything before Jan 2014 are already in the database backup), you may find it easier to just use your web browser to save the few pages of PMs that need transferring, instead of getting the tool to do it for you.
For reference, here's a rough outline of how I've tested (only on a test account so far, since I want to be absolutely sure it doesn't accidently navigate a link that would perform a destructive action, one of the potentialdangers of crawling through a logged-in forum session):
1. create a directory (folder) to serve as working directory for WinHTTrack for crawling your PMs. Then create another directory under it with a simple name like "myPMs".
2. on web browser, logged in to desired user account with "stay logged in" checked
3. grab/export the cookie file associated with lemmingsforum, which contains the data necessary to allow WinHTTrack to use your active logged-in session as it crawls (obviously needed in order to browse your PMs). You may need a tool besides your own browser to properly get the cookie file, as WinHTTrack requires the cookie file to be in a specific format, which may not be the one used by your browser for storing the cookies. You may also need to slightly modify the contents of the exported cookie file to make WinHTTrack happy. For example, the tool I used seems to leave an extra "." before "
www.lemmingsforum.com" inside the cookie file, and I had to remove that extra period to get things to work.
4. Put the exported cookie file into your directories from step 1 (one copy in the working directory, and another copy in the "myPMs" sub-directory or whatever you named that), make sure the filename is exactly cookies.txt
5. now start WinHTTrack and start a new project. For "Project name", set it to exactly the name of your sub-directory (eg. myPMs) from step 1. Set the "Base path" to the working directory from step 1. Hit Next.
6. Set "Action" to either "Download web sites" (if first time) or "Update existing download". For the "URL", use "
http://www.lemmingsforums.com/index.php?action=pm" (no quotation marks of course). Then click "Set options". An "WinHTTrack" options window pops up.
7. Here's the important part: go to "Scan Rules" tab, and add the following to the end of the line you see in the text box:
-*?topic=* -*?board=* -*?action=* +*?action=pm* -*sa=* -*togglebar*
A quick explanation of what this does: the "topic" exclusion blocks crawling of forum posts, "board" exclusion blocks crawling of forum boards, and "action" exclusion blocks lots of actions you don't want the crawler to crawl and trigger unintentionally, like the link in the "logout" button for example (or worse, the "delete" buttons for your PMs!). The "action=pm" inclusion then allows the crawler to crawl just the URLs that are specific to your PMs (both the inbox and sent). The "sa" exclusion blocks site actions, which are associated with other unwanted actions like "prune messages" or changing your settings. The "togglebar" exclusion blocks the "<<" thing you see near the top-right of the PM pages, which apparently changes your user preference of the way the PM page is laid out.
8. Now go to "Limits" tab and set "Maximum mirroring depth" to a reasonable number. My suggestion is to look at how many pages of PMs you have in your inbox and in your sent box, take the maximum of the two, and then add like 3 to it and use that number. I actually don't know if you really need to set a max here, but it does ensure that the crawler won't get into a runaway situation where it is not able to accurate detect things it already crawled and therefore never stops crawling. Higher number simply means you are more likely to get pages saved by the crawler that are effectively duplicates.
9. Now click OK to commit the settings. Then "Next" through the rest and let the tool do its thing. It may take some time before it's done so be patient.
10. Once it's done, click the " view mirrored website" button and see what you get. If all goes well, the page that you first see would be a mirrored copy of your PM inbox page. If instead you get the page that asks for username and password, then the cookies you set up from steps 1-4 are apparently not getting used. Manually browse through a few links to verify that your entire inbox and sent box get mirrored (by seeing that the URL displayed in the browser is referring to a local file on your computer, rather than the usual HTTP web address). (Note: you may notice that the user avatar pictures are missing in the mirrored pages. This is a side effect of the "action" exclusion rule, since the URLs to the avatar pictures do contain that "action" keyword in their URLs. While it can fixed fairly easily by refining the scan rules, it really doesn't matter since the point is just to capture the contents of your PMs.)
Anyway, with that being a success, I'll take a look at capturing the PMs for my own account and for the QuizMaster account, and see if namida can do anything with the resulting files.