I have several sites running on Drupal and occasionally I come across this issue - usually after I upgrade and I forgot to copy all of the custom commands into the new directory. How do you disable register_globals when running on 1and1 hosting?

There are two options for turning off register_globals: you can create a new php.ini file or you can add it to your htaccess file. Here are the directions.

PHP.INI File
Just create a file file in the root of your drupal installation and name it php.ini and then paste this inside:
register_globals = false
memory_limit = 40M

.HTACCESS File
Or you can add the following to your .htaccess file that is also located in the root of your drupal installation:
# Disable register_globals
AddType x-mapp-php5 .php