The runtime error CONVT_NO_NUMBER occurs when you call transaction SE30[@more@]Reason and Prerequisites

The system creates a performance data file that has a corrupt header. This can only happen if you have activated runtime analysis using transaction SICF.

Solution

Open the debugger in the session in which the ABAP runtime error occurred. The termination point is at the following code:
case L_HEADER-AGG.
when ...
When you double-click on L_HEADER-AGG, the contents appear in the field display. If the value is not 0, 1 or 2, then the error described here has occurred. In the field display, write in the line under L_HEADER-AGG p_fname. The content of this field is the name of the file - this causes problems. This file must be deleted by the system administrator.
If you do not need any more performance data files, the system administrator can delete all of them.
Apply kernel patch 126 for Release 6.40, if you have not already done so. The error is corrected as of patch level 57 for Release 7.00.