can someone help me
when i open a ROM file with dualis i only get a black screen
does someone tell me what to do?

what file are you trying to run?

Well, it could be that that Dualis doesn't support the ROM image in question. Black screens are not something the end-usder can "automagically" fix, you know.

Imperfect emulation.

it is a nds-file
but with every Rom-file I try to open i geta black screen

Is it a commercial ROM? Support for those is pretty low as of current. Only PD ROMs are supported by most DS emus.

What roms have you tried?

Well,i have try many games wif tis emu and all end up wif black screen....i think commercial roms still not playable wif any NDS emu right now

Yeah, that's true. As you can see by looking at the posts here, the fact that commercial ROMs don't work on emulators is pretty much common knowledge.