Besides what stefanero asked, tell me what is your aMule version?
You are probably using skins. There is a bug in skins that is fixed on the CVS tarballs. Open the file ~/.eMule in an editor and look for these lines:
[MiscGUIOptions]
UseSkinFile=0
OR
[SkinGUIOptions]
UseSkinFile=0
Depending on your aMule version, you will find one or the other or both

. Make sure that UseSkinFile is set to zero. If that is not the problem, please report.
Cheers!