Well, kopete 0.8beta2 installs its binary into '/usr/bin/kopete', and thats not a path variable, I think.
So, in KDE, press 'Alt+F2', and type in this opening box '/usr/bin/kopete' (without the ' ). Kopet would start and shows you everything you want to see. :-)
To uninstall the kopete-7.3 rpm, try to type 'rpm -e kopete --test' in a console.
It will show you Error Messages or someting like that, if everything goes fine, type it without the '--test'.
Good luck,
liquidat