OK, but before the system info, here's an update on my problems:
1) I was able to import/play M3U playlists as long as they are located in my root directory (c:) but if I have them in any subdirectory (and I tried various ones) they won't play or import. Now that I put them in root, they appear under "Mixes" in my Playlists area.
2) Once they were imported, MJ messed up the path by adding a "c:" in front of the \\machine\sharename\". So I used the very cool feature of Find/Replace in field Location to fix everything.
So for now I'm OK, though it took a lot of extra work on my part to do something this simple. Also, I'm trying to figure out if there's an easier way to copy these playlists to another computer running MJ without going through the same lengthy process.
Am I the first person to try importing UNC-based M3U playlists? I can't believe that my computer is somehow causing these types of issues.
But here's my info:
Media Jukebox 8.0.372
Install Path: C:\Program Files\J River\Media Jukebox\
CPU: Intel Pentium 4 1700 MHz MMX
Memory: Total - 130 MB, Free - 0 MB
Resource Info: System - 37 %, GDI - 53 %, User - 37 %
OS: Microsoft Windows 98 SE
Internet Explorer: 6.0.2800.1106
ComCtl32.dll: 5.50.4916.400
Shlwapi.dll: 6.00.2800.1106
Shell32.dll: 4.72.3812.600
wnaspi32.dll: 2, 0, 0, 0 , ASPI for WIN32 DLL, Copyright © Adaptec 1995
Aspi32.sys: N/A