Diagnosis
Probably the following scenario took place:
The archive was initialized.
Before the first run of the P46 Company Car report and directly afterthe initialization of the archive an Infotype (Company Car) 0442 recordwas entered having its start date before the 06.04.2002. It means thisrecord has not been captured in the archive during the initializationof the archive as it should.

Procedure
In order to fix this problem please contact SAP.