No matter how you solve the problem, you will have to install the 32 bit flash player. Now you have 2 options:
- Remove the 64 bit browser, install the 32 bit one and install only 32 bit plugins in there.
- Keep the 64 bit browser, install nspluginwrapper
and then install 64 bit plugins directly in the browser and those that only have a 32 build (as flash...) with nspluginwrapper.