I've recently installed Dosbox 0.74 on my Win7 Ultimate system. I experienced the backslash issue. So I loaded up keymapper and solved that problem.
Unfortunately, I've discovered other keys that have the same problem.
The ones I've found were:
` key
= key
[ key
] key
' key

Now using keymapper I managed to fix only the ] key. I have no idea why the others will not stick. If I load keymapper and try to get ` key working. I map the key and save and exit keymapper. I press the key and I do get a ` but sometimes it starts repeating ` until I press it again. If I close dosbox, it doesn't remember that key. So far it only remembers my \ and ] key that I have mapped. Any suggestions would be cool.
Thanks