If the checksum error came back so soon after changing the battery, this suggests either:
a) a bad battery – try another one.
b) possible software oddity or cosmic ray causing non-battery related checksum error. Clear it and try again.
b) hardware problem on Eclipse causing excess battery current. This is the least desirable option
If there is a bad checksum condition, it is usually harmless, but can cause crashes, etc. Needs to be resolved before looking at what may be symptoms of the same problem.