Chuck E, your issue with. "An error occurredThe following details are provided:E: The value 'wheezy' is invalid for APT:default-Release as such a release is not available in the sourcesE: _cache->open() failed, please report."
Can be easily resolved by editing the file /etc/apt/apt.conf.d/00knoppix
add the # to the beginning of the line APT:default-Release "wheezy" ; or remove the word wheezy.
All will work fine with synaptic after you have saved this edit.