Well until I found that thread I thought you would have used boinccmd.exe not boinc.exe to attach manually.
Yes I'm also not sure about renaming the folder, the URL that BOINC is complaining about may be referenced somewhere else as well.
A project that has short running tasks you could just leave it as it is and see if tasks upload and report correctly but with such long tasks it would be frustrating if you completed some Climate Prediction work and it errored because of the incorrect URL.
Hope you manage to fix it, I haven't done any CPDN for yonks. If I remember correctly I used to run one of the climate model applications on Linux because it was a bit faster than Windows. Don't know how the current applications compare regarding OS.
I just had some of my mum's Mylanta, what weird tasting stuff, like fake mint taste mixed with chalk. Needed it because ate too much at a delayed Christmas dinner last night.
Hope your Christmas was fine, I scored some sensational Mareeba mangoes, sun dried Turkish figs, a bag of sencha tea and a Skoda Octavia wagon. So good to have a wagon again, haven't had one for 30 years since my HJ Kingswood V8. Octavia has so much room inside and is a corker to drive, engine's only 1.4 litre, but light weight plus turbo FTW.