The club's May 14 date with AC Milan at Giants Stadium, near New York, clashes with the US national team's friendly with Jamaica in May 16.
A club spoeksman said they would try to re-arrange the match but it was likely to be next year, before it could take place
"We have been doing everything possible to make this happen."
The US Soccer Federation confirmed their rules could not be broken, even for charity matches.
A federation spokesman said: "Everything was taken into consideration, including the fact it was to raise money for families of victims of September 11."
Let's hope the game can go ahead at some time in order that the cash raised can go to the worthwhile intended cause.