I have no clue what you did. It saddens me to say this, but the "Repair" function in the installer is useless, so most likely it has completely messed up everything. Therefore uninstall again and use the CS3 clean scripts before attempting a new install. Copying presets is ill-advised except for the ones you created yourself. Others from AE7 may not function at all in CS3, so there's no point in overwriting the ones the CS3 installer puts in place. As for your plugins - depending on what they are, a proper re-install of them may be required. Some plugins and plugin suites install additional files and store their paths in configuration files or the registry, so they may refuse to work without them.

Mylenium