If you need SCIM support in Mandriva 2007 for both GTK and Qt apps, add this to your ~/.i18n or /etc/sysconfig/i18n file:
XIM=SCIM
XIM_PROGRAM=/usr/bin/scim
XIM_ARGS="-d"
GTK_IM_MODULE=xim
QT_IM_MODULE=xim
EDIT: Looks like SKIM, the KDE frontend for SCIM, sometimes gets a bit confused with this. Omit the XIM_PROGRAM and XIM_ARGS lines mentioned above and enable autostart in skim (use the settings dialog or set Autostart=true in ~/.kde/share/config/skimrc) if you use KDE.