namespace AppCorLib
QuickFixInterface::QuickFixInterface(std::string configFile,int port,std::string host,int type):Interface::Interface(port,host),mSettings(configFile),mScreenlog(mSettings),

This looks like a C++ initialization mistake to me -- you need to declare mApplication *before* mAcceptor in your header file.  Currently you have it the other way around, which means that mApplication has not been constructed at the time you pass it to mAcceptor's constructor.

Mike Gatny
Connamara Systems, LLC