On top of that, the data in the last line read looks fine.

21:46:29 2020-01-26 21:46:24.24 C M  -18.8   25.4   25.4    2.9  26    4.7   0 0 0 00003 043856.90722 1 1 1 3 0 0
21:49:39 2020-01-26 21:49:34.34 C M  -19.3   24.9   24.9    2.6  27    4.8   0 0 0 00003 043856.90942 1 1 1 3 0 0
And this is so strange ... trying to see the original attachment Run-time_error6_ACP_Web_Page.txt now causes the forum to report unreachable, and after trying several times I got a Firewall Block notice from the forum! I had to answer a Captcha to get in. Dang another thing to deal with :-( I removed the file to prevent others from being tempted. I don't want to be diverted to that!

If I didn't mention it the reason you saw the raw HTML/ASP in the web page is that when ACP popped that error alert box, its message loop is trapped and the ASP engine cannot run to render the page. The way the little OEM HTTP engine works and my add-on of the ASP engine, has this wuirk when ACP is showing an error alert like that. It can't be fixed, but the error alert is essentially fatal anyway. And that's the problem we're looking at. The fast that it happens so infrequently is making this difficult.

Anyway the data in the weather line looks fine. Sp let's test whether there is an uncaught error in the ACP.BoltwoodFile weather server. Open it up in a text editor and find the highlighted XML

    <component id="BoltwoodFile">
        <?component error="false" debug="false" ?>
        <registration progid="ACP.BoltwoodFile" ...etc
Change to


and save. Next time this happens let's see if a more meaningful error alert appears.