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I didn't see any information on that system on the web (I only took a quick look, though). Is the system a Sony/Gylling S-260?
If you connect the cables backwards (e.g. "+" cable into the "-" terminal), it won't damage anything. The speakers will be out of phase, though, so the sound won't be as intended. If you do a search on the internet for "determine speaker phase", you'll find some info on that. If the speakers are out of phase, the imaging and bass will be degraded.
So, you could hook them up one way and listen, then switch the cables and listen, and then decide which hook up sounds the best to you.