Thanks, glocK_94.
Installed the GTK runtime. Oddly, it wanted to install in a GTK subdirectory of the chosen path. I knew this would give problems, since GTK 2.0 runtimes are usually installed in GTK/2.0 of the Common Files directory. Anyway, I proceeded.
Next I tried GAIM 1.5. Needed GTK 2.6.9.
GAIM 1.0.1 and below all wanted a GTK 2.4 version.
GAIM 0.79 is the last that accepts a GTK 2.2 version.
GAIM 0.76 or so was the version I tried before, I think. It gave me problems. So I closed everything first. GAIM.DLL yielded an error. Ran Dependency Walker on it. It couldn't find any of the GTK files.
I saw that the GAIM downloads section also offered GTK runtimes, so I looked at the list. No GTK 2.3, but the last GTK 2.2. I'm starting to think that there never was a GTK 2.3. Actually, if the versioning is like Linux' kernel, it was probably an unstable developer version. There's no GTK 2.5 either.
Now GAIM ran. Looked at the system resources. 94%. Tried to open a second instance, got a white error box without text with a Close box. Then I couldn't open anything from my desktop anymore. I still had one folder open, so I pulled that up and looked at the system resources. 94%. I closed GAIM. Explorer became unresponsive. Eventually I could terminate it. Then I couldn't do anything anymore. MSGSRV32 hanged as well, it was terminated. Selected "Shut Down" from Ctrl + Alt + Del. It didn't do anything. I couldn't even Ctrl + Alt + Del anymore. The Reset button was my last exit.

EDIT: By the way, since we're on the subject of GTK anyway, I have to wonder what the webmasters of the GIMP website are smoking.
QUOTE
Starting with GIMP 2.2 and GTK+ 2.4, older versions such as Windows 95 are not supported anymore.
How do they intend on supporting GIMP 2.0 on Windows 95 when it requires GTK 2.4? Pssh.