You can download the latest Sea Monkey releases here and 64-bit issues are a thing of the past now:
It's a little tricky if you are running a 64-bit OS which most people will be.
The weird thing is that the Seamonkey website for Linux seems to only provide a 32-bit download.
seamonkey-2.49.2.tar.bz2
Seamonkey is still provided as a tar.bz2 which you need to extract and run manually.
First........