Recently had the hard drive replaced in TalkPath 303-06 with flash drive and new operating system. As I have been trying to configure things using ADMIN (no backups,vendor who had them is gone), I got a message:
"-ERROR could not write Time CTRL:NTYTIME"

What does it mean and anything to worry about?

Should Time Control 100 have named itself Basic COS?

No, time controls have no name by default. If you're not using time controls, just set all of the voice lines to menu 100 and see if it runs properly.