Problems with the export to VA Server

[Manu]

Hi,
i have the message with export to VA Airlines
"Error unable to find the flight in Log file. Flight Id dosn't match".
I have 200 Flights in the Logfile and the 5 first entries in the Logfile haven't any Flight Id.
Because i have deleted the old VA and export the Pilot to the new VA.

How can i delete the first 5 entries in the Logfile??
Thx...