Custom error message in VC02

Hi All,

I am executing transaction code vc02.When I click on output button at the top, it shows an output entry with RED icon. I tried to find out the reason for failure from processing log button, I found a custom error message is responsible for red icon.I noted down message class and message number and tried where used list in se91 however not hits are found.Can anybody guide me how to debug this kind of situation?(The standard VC02 seems a bit complicated and with no entries found for custom message in SE91 ITS BIT CHALLENGING).

Thanks,

SD