You've been informed correctly, unfortunately. There is only one way to deal with a warrant and that is to turn yourself in. Otherwise, it will be out there against you and can raise its ugly head just like it did to potentially cost you a job.
If it's a misdemeanor charge, the place where you're at risk of an arrest is Maryland. If the warrant is discovered in other states, Maryland won't extradite you for a misdemeanor, so you'll just be warned that you ought to take care of the warrant. If it's a felony warrant, you are at risk of an arrest any and everywhere.
Warrants never expire. Yours will be out there against you for the rest of your life or until you come back into Maryland and deal with the criminal matter, whichever comes first.
When you do come back, you may have to face some time in jail. The best way to minimize that would be to get a lawyer involved. He or she can find out more about the situation, talk to the police and the prosecutor if it's been filed and broker a voluntary surrender which would make your processing time and time in the system as little as possible before you see the judge.
If this check was yours, a case like this after ten years should be easily resolvable. It may even be dismissible if the state no longer can find its witnesses after all of this time. If the check was never yours and that could be documented, this case could also be dropped against you.
But again, the only possible way to get rid of this warrant is to return to Maryland and surrender to the authorities.