waynomat's problem got solved, ioftpd 4 uses 'passwd' and 'group' instead of 'UserIdTable' and 'GroupIdTable'
updated in 1.1.17:
- ioBMonitor added to activity lists.
- grouped the 3 ways to get user activity into 1 tab with 3 subtabs (ioGui will remeber last used tab as default)
- full line is now colored in activity lists instead of only username.
- added checkbox in user activity to stop refreshing if needed.
- fixed menu popup on tray icon: it doesn't hang anymore. (
edit: it still hangs 
)
- improved sorting in browser: should now always split dirs & files, and remember sortorder.
- browser is now resizing in height as well.
- VFS file can now be set for users & groups. Once u set it, u can't delete it unless u manually edit the user/group file.
issues:
- sitewho.exe seems to skip alot users, only 30% of the times all people get listed, or is it just me?
- empty tab item, didn't feel like going through the trouble to delete it
(no changes in ioGuiExt for those who are upgrading, just .exe and some .ini settings)