tx_mutex_get returns error in threadx synergy

Hi all,

I have created a timer where i call some function. In that function when i try to acquire the mutex using threax api

tx_mutex_get(&m_hTimerMtxLockHandle, TX_WAIT_FOREVER);

it returns TX_WAIT_ERROR (0x04) ( A wait option other than TX_NO_WAIT was specified on a call from a non thread.)

and when i pass the 2nd argument as TX_NO_WAIT

it returns TX_CALLER_ERROR (0x13) ( Invalid caller of this service.)

What could possibly go wrong ?

Thank you :)