We've just started a discussion about UMPlayer over at portablefreeware.com. The fonts cache is written and left behind in "C:\Users\user\AppData\Local\MPlayer". SMplayer writes it under ".\fontconfig". Any chance this behavior can be changed (searched in Preferences with no luck)?
I also have a problem with UMPlayer not remembering the time position (when store settings in multiple ini files is enabled).
I am using "UMPlayer-athlon-mt.exe" built on 2010.01.18 on Win7x64.
Sorry for the late replay; but we're on it. We're super busy trying to release the Mac version (OpenGL is a bitch) but I hope we'll be able to fix all these issues very shortly