If you receive this message:

kio (KMimeType): WARNING: KServiceType::offers : servicetype Skim/Plugin not found

then please make sure that all the *.la files are installed properly to a dir where KDE can find. If you have the *.la files in place and it still refuses to start, then please try to

chmod 755 /lib/kde3/skim*.la

(Attention: this is assumed your skim was installed to $KDEDIR. However in some distros, the prefix may be set to /usr or something else, please check it first.)

References:

Gentoo bug report: skim (scim-panel-kde) won't start although scim-panel-gtk works