In the Freelancer directory you'll see a folder called EXE, go into that. In there, look for a file called "mpnewcharacter.fl" and open it with notepad (or any text editing program).

Near the top you'll see this line:
money = %%MONEY%%

Just change that to include whatever amount you want. So if you want to start with 50,000 credits, it would look like this:
money = 50000

I hope that helps.

I have looked in EXE but i cannot find a file called "mpnewcharacter.fl" any idea as of what is wrong?

That file should be there, if not run flserver.exe then check for the file again.