A script that reads the content of the VARA UC_EX_HOSTCHAR and writes it into another VARA started to fail at some point in time with the following error:
Status: FAULT_OTHER - Start impossible. Other error.Last message: U00003712 Missing key for accessing variable 'VARA_NAME'.Automatin Engine 24.4.0HF3
Empty line or blanks added into one of the columns of the VARA that was being read (UC_EX_HOSTCHAR) from client 0.
This could be found while checking the modification time of the VARA UC_EX_HOSTCHAR, the time when the issue started to occur matched the time that this VARA had been last modified (in general - History - Modified by):
Edit the VARA that is being read (on this case UC_EX_HOSTCHAR) and delete the last empty line and save it.
Then the script should run fine again, else restore the VARA to the definition before the script stopped working and that should also solve the issue.