No. There is no synchronization. This message is shown in console: ...
Are you sure you had receiver_76 in the directory before trying to resync? As block 304000 is where it rolls from 75 to 76.
Of course, I'm sure. I replaced it with this file
http://devcoin.darkgamex.ch/receiver_76.csv for the last time before synchronization.
Had a look at the code linked here:
http://devtome.com/doku.php?id=devcoin#receiver_filesBlock 304000 is when receiver switches to newer file. Assuming height 304000, step 4000 therefore refers to first address of new receiver file (receiver_76):
First address in receiver_76 is 15MZRa1cPUVChs6XpzyAfGox5nvPVpSvok
But first address in receiver_75 is 1KZKMYixw4PDtu5ZbKqrahRWeAgputuVoc
As those two addresses correspond to your errors, all I can think is that client hasn't properly closed/restarted in resync to pick up receiver_76?
That's just my uninformed guess. Anything more informed will need someone more familiar with the process.