run the repair on the launcher after login (lower left cog) that should hopefully solve the companion crash.
the below may stop your crashes in esselles
1.Right-click on your desktop background
2.Select "NVidia settings"
3.Go in the "Manage 3D settings" option
4.Under the "Program Settings" tab then add swtor.exe if not already listed
5.Find the "Threaded optimization" option and turn it "OFF" to force it off.
6.Apply the modifications
These steps did not resolve the issue. Other things i have tried include repairing the MS Visual C++ 2008 install for both 32 and 64 bit versions. Well i have passed by The Esseles now anyway but i did just run it solo to test out the above changes but no luck.