I've been tracking this problem for about six months, now.
When we started the set up for Civil 3D 2014, I migrated the Pipes Catalog from 2013, and started seeing error messages when starting Civil 3D. Every time I make a change to our default template, the errors come back. I have to go into AeccPartParamCfg.xml and change the name of every one of the custom parameters, to make the errors go away. After renaming the custom parameters, the errors go away, but I have to fix a lot of drawings and templates.
I'm wondering if there's something wrong with the way I have the AeccPartParamCfg.xml file set up. Any help would be appreciated.