I just recently got DCS A10 and I'm having JTAC issues as well. I started getting loops of "Abort abort abort" then I started getting no reply after reading back to JTAC, or no data received. I'll try disabling allied flight reports to see if that helps. Any tips on locating ground targets without JTAC?
EDIT
That seemed to make it worse. JTAC read me the 9 line, requested further talk-on. Never heard from him again.