Hi,
You should check this article
How to Create Exceptions or Exclusions for Tamper Protection Alerts that have already been logged
http://www.symantec.com/docs/TECH92553
If you have already created exception and still facing problem then need to follow this workaround
Possible Workarounds:
It may be possible to work around or resolve this issue either by updating the application for which the Tamper Protection alerts are being generated, or by updating the SEP client version on the affected machines. A future version of the product may make the Tamper Protection alert optional, offering a different alternative to exclusions for avoiding overly frequent alerts.
Symantec Endpoint Protection (SEP) clients generating Tamper Protection alerts on excluded applications
http://www.symantec.com/docs/TECH171057