Trouble?
If the game didn't load properly, exit to DOS, and copy your backup save game file onto the one you changed. If there was more than one occurrence of the hex code when you changed them only change one of them before saving changes and loading the game.

If it still doesn't work restore the backup save game and change a different occurrence of the hex code.
continue to change different occurrences until when you load the game it works, (or you run out of occurrences, and it doesn't work)

A good way to do this is load the un modified save game, run the search as specified earlier, and put a mark on the paper where you noted the hex codes etc, keep running a search and marking the page until there is no more occurrences of the hex code. eg.

1000 credits
c:\games\privater\game0003.sav
E8-03-00-00
1000000
40-42-0F-00

I I I I I (<- here are the lines)

Then change the first occurrence, run the game, if it doesn't work, restore the save game backup,
cross out the first line, run a search twice then change only the second occurrence, and run the game, keep this up until you either run out of lines or it works.

Possible problems:
When you load the game, it shows you have; -say $100000, but the game keeps telling you that you are out of cash when you try to spend it.

This is an interesting bug I encountered a few times, from what I could tell the game stored the number it showed on screen in one place in the save game, and then stored the amount of money you actually had in a different place!
The way to fix this is to load the save game into the editor and find which occurrence changes your money and which occurrence changes how much money it says you have, and set them to the same number.
 

When you load the game, the amount of money you have is shown as a negative number, or you are dumped into dos with some sort of overflow error when you load the save game.

This is because you either got greedy and changed your balance to a figure higher than 2147483647 or the maximum figure the game allows, or you simply changed the wrong part of the file, select a lower new balance for your games money, and follow the "Trouble" section above.