If you need to add entries to your web.config and are using connection strings or AppSettings with parenthesis or <,>,& you will need to escape these characters as they are invalid in XML markup.
A simple way to fix this is use an online HTML encoder. Simply copy paste your code into the encoder on this site: http://www.opinionatedgeek.com/DotNet/Tools/HTMLEncode/encode.aspx
Paste the output into your web.config markup. Run your program and your variable will load correctly!