Hi, I've been going through this process lately as well of getting all of the plugins I want working. I am using the RC8 though, but the same process should work for you for .7.2 as well.
Your best option is to remove all plugins from your main config file and load just the plugin manager plugin and global config if you are using this one as well. (I decided for the time being not to use the global config and have the configs in each plugin folder.)
Also be aware that some plugins wont work with the plugin manager, so see which ones come with RC and which come with the plugin manager. I've still found for me anyway that even some plugins are better commented out in the plugin manager config and loaded in your main config file.
Now enable logging in your main config, and use file, you can now check your /logs/error.log file for issues with your plugins when you activate them.
What I did was to do set up one plugin at a time, restart Apache, refresh the login page, check the error log for anything, then login, check the error log again, then depending on the plugin activate it, check error log, use the plugins function, check the error log.
This was I was able to either update the plugin if there were depreciated hooks (most common error) or fix what ever other error there might be.
Also make sure that you have the latest version of all of the plugins you are using.
It has taken me around a week during the evenings to get just about everything I want to work now, my php experience isn't the greatest, but I am a programmer so I can general work out what to fix.
Another suggestion, make plenty of back ups, both files and of your database.
Enjoy.