File Numbering Issue, files number not being updated...

Question

Hi All,
I have an interesting problem, I need to create save files in the following format SV_XXXX.msg in a specified location.  This I am doing I have a folder with SV_0000.msg to SV_0132.msg
however it will not create SV_0133.msg onwards, it just appears to over write SV_0132.msg with the last data.  Is there a reason for this or do I have to rework the way I am calculating the number?
Glenn