Tried Googling "Can't keep up! Is the server overloaded?..... " and although no real solutions
- a lot of suggestions seem to point towards a server problem (something wrong with the world map due to excessive lag)
PC hardware is not up to scratch (too much CPU usage, not enough memory assigned or Java (using 32bit on a 64bit OS for example))
Since you have problems in Single player as well as Servers.. it seems to point towards a problem with your hardware so not only a crash log will help, but maybe also a DXDiag report may useful as well
Say something silly, Laugh 'til it hurts, Take a risk, Sing out loud, Rock the boat, Shake things up, Flirt with disaster, Buy something frivolous, Color outside the lines, Cause a scene, Order dessert, Make waves, Get carried away, Have a great day!