I've actually found another bug related to this. I'm not sure if it should really be considered a bug - but I'd like to think so...
Anyhow; as you can tell by the topic title, the program crashes when tagging an unusual amount of files. In my case, it is 226 FLAC (encoder: libFLAC 1.2.1 20070917) files exactly. To reproduce it, I simply: select all files (via CTRL+A) -> copy the tags (via CTRL+C) -> remove all tags (via the cross symbol in the toolbar) -> paste all tags back (via CTRL+V). I use VorbisComments to tag FLAC. The progressbar then stops, and I'm prompted with an error report dialog (not Windows' own prompt). Tagging all of the files separately in smaller batches (50 each) solves the problem.
The second bug is involved in the process above - when I select all files and remove the tags (same method as mentioned above), it will start removing the tags, and when it's done approximately 95% of the process, it will stop for around 10 seconds. Then it successfully finishes and the "removing tags" window disappears. Interesting note: moving the mouse pointer even the slightest after the point that it stops, finishes the process instantly (I've compared at least five times).
I'm using Windows XP SP3 Professional (retail, with no updates installed, except for possibly additional ones needed for some services and so). I've tried your latest development build (v2.48b), and the problem existed in the regular version of v.2.48 as well.