Here's the link to the troubleshooting procedure for the Powerbolt, wherein beeping is discussed:

http://www.weiserlock.com/Support/Faq/50160000000HhhZAAS.aspx

If this doesn't help, I recommend contacting their Customer Support for further advice and parts:

http://www.weiserlock.com/en/CustomerService/ProductSupport/SupportContact.aspx

Good luck!