If you have problems later with the game, those 3 errors may have caused corrupt or missing files. You don't need to worry too much about it if everything runs fine, though.
My brother had a laptop with an optical drive that would only recognize a disk about 50% of the time, requiring an eject/insert to try again. Once it detected the disk, though, it didn't have any problems reading it.
With random errors when installing, you may want to check your RAM, as well. I had a piece go bad a couple years ago, with the only symptom being DVD-Rs failing to verify after burning, at first occasionally, then getting progressively worse (at first I assumed a new/cheap brand of DVD-Rs were at fault...).
Memtest86MS Windows Memory Diagnostic