have to start with a fresh setup, e.g., delete your picasa setup folder for each user-account having used picasa:
rm -fr ~/.google/picasa
the following is valid for each user-account:
1) upon first launch of picasa your personal picasa setup will be setup
2) during the second start of picasa you will be asked if you want to add IE6 to Picasa in order to login to your google account. If you do not use a google account you can skip this installation step which is only run once, else follow the instructions.
3) starting with the third start of Picasa all is set up, either with or without Google account login, no further questions asked
if you have skipped step 2 or want to add the Google account login feature later on, first close picasa and then enter the following command in a terminal:
rm -f ~/.google/picasa/3.0/drive_c/windows/system32/idontwantie6
then run picasa and follow the IE6 setup procedure.
hope this helps,