A couple of Dosbox questions

I want to run a Dos program on my netbook using Dosbox - it works OK, but getting it to start is a pain because I have to set the path etc. and the netbook's ~ key doesn't work under Dosbox, it comes out as an @ instead. Can't find ~ at all under DOS. I can get round it by using CD ../ to get to the top of the file system, then changing directories down, but it's a bit of a pain. Any easy alternative?

What I would ideally like to do is set up a link that starts Dosbox and loads the program automatically - is there any simple way to do that?

And another stupid question...

Are there any hideous security etc. problems with Dropbox I should know about? It sounds good, and my family and I seem to be exchanging a lot of baby photos etc. which it might help with, but does it leave any holes in the PC's security, bombard you with spam, or anything like that?