SAP Message 53003 - Time ticket data cannot be entered on this screen

Diagnosis
This screen is for several time ticket types. Here you can displaydifferent types of time tickets by entering the personnel or groupnumber and if necessary by entering additional key fields in order torestrict the possibilities and by choosing the function "additionaltime tickets". You can select the time ticket displayed and maintain iton the full screen. New time tickets cannot be entered as you have tospecify a time ticket type.