So, the problems discussed on this thread came back - no page menu editor, and 500 server errors kill the entire site when any type of form creation plugin is activated.
After some googling, found an issue with 1&1's hosting regarding memory allocation for php.
The fix:
Create a text file and name it “php.ini” (without the quotes ) and with a single line of code in it:
memory=20MB
This file has to be placed into the directory /wp-admin/ within your WordPress installation.
Everything's fixed - whew.