Are you installing to an image file? Windows 98 isn't meant to install in DOSbox otherwise. Keep in mind though, that the drivers will all be 16-bit and hence the installation will run very slowly, if at all. If you've still got your heart set on it though, there should be installation guides on the net. Windows Xp Sp3 Ghost With All Drivers Iso. Check the VOGONS forums too, they normally have stuff like that. VP2k7 is a better option, as the posters above have stated, though an older version of VMware Player would do the job as well. Not VirtualBox, it doesn't support Windows 9x too well.
It's a bit of a pain in the ar*e, but it's possible. It's a shortened version (with a lot less pics) of a how-to I wrote Last year. Prinsip Kerja Mesin Bubut Pdf.