In versions earlier than 3.3.14, there was a fatal error that occurs when you enable both Advertising Manager and Adsense Manager. To resolve this, simply delete the plugin 'adsense-manager' from the plugins directory.
If you do not have FTP access to your server, but have access to and are comfortable with phpMyAdmin, please follow these instructions:
1. In phpMyAdmin, go to the wp_options table.
2. Copy the value of the option_value column, where the option_name is 'plugin_adsensem'. This should be one of the last rows in the table. Paste the value in notepad or something.
3. Delete the row in wp_options where the option_name is 'plugin_adsensem'. Make sure you ONLY delete this row, and not all rows in the table.
4. This should get your WordPress installation up and running.
5. Now that you are up and running, deactivate the 'Adsense Manager' plugin.
6. If you want to keep your old data, edit the wp_options row where the option_name is 'plugin_adsensem' (it will be created again by Advertising Manager). Paste the contents of the field that you saved from before back into the field.
7. Advertising Manager will automatically upgrade this data with no problems.
If you have any questions, skype me (switzer) and I can walk you through the process.