error: expected constructor, destructor, or type conversion before 'void'

Hey, I am currently verifying my code.
But I got error message like this:
board.cpp:257: error: expected constructor, destructor, or type conversion before 'void'

in the line 257 of my board.cpp it contains like this:
__interrupt void TIMER1_A0_ISR(void)

its from my Timer A0 interrupt service routine, so the general content is looked like this

#pragma vector=TIMER1_A0_VECTOR
__interrupt void TIMER1_A0_ISR(void)
{
__bic_SR_register_on_exit(LPM3_bits);
__no_operation(); // For debugger
}

i suspects that my code cannot be generated because I save my file into .cpp instead of .c or the other way around, but when i tried to save and run it in .cpp format. But I kinda confused, because both ways are not working.
So, if someone knows what the problem is, can you tell me?
Thank you!

Stella

Did you write that file, or is it a library ?
Can we see it ? It is online ? where ?
Is that MSP430 code ? Do you know this is the Arduino forum ?