I just found out why my wordpress installation was not working as I expected.  My wordpress updates would hang/not complete and the plugin installations would hang/stop or come back with errors.  As it turns out, 1and1.com defaults to PHP version 4 to execute the php scripts.  So, I just had to add the following code to the .htaccess file in my root of my blog directory:

AddType x-mapp-php5 .php

After that, everything started working real smoothly.  So, make sure you update that PHP4 to PHP5 if you’re using 1and1.com.

–Ben

Reference:  1and1.com