MSP 430F2274 receiving Interrupt not triggered

Hello;

I am running the MSP430F2274 (CC2530 ZNP mini kit) examples for communication through UART. I have an FTDI USB 3.3V cable with USB on one end and UART RX and TX on the other. The hyper terminal and the receiving java program correctly receives the value from the MSP device. The MSP device is running in a loop and transmitting A-Z and this part of the functionality executes without any problem.

When I transmit from the java program the MSP interrupt for reception is not triggered. The problem then should lie in the java program / hyper terminal i.e on the transmitting side or the code of the MSP device on the receiving side. To eliminate the transmitting side, I looped back the RX and TX connections (on the UART side) of the FTDI's USB cable. The characters transmitted was correctly received on the console. This probably indicates that transmission till the MSP device is okay, which eliminates cable, connections (Rx/Tx) and settings. The transmission from the device was earlier tested indicating the baud rate and 8N1 to be correct on both sides. I dont know why the interrupts are not being triggered.

In the program shown below, which was tested on the device . If I change  IE2 |= UCA0RXIE ; to  IE2 |=  UCA0TXIE;, then the output prints Hello World.

The initializing code for UART is working on the kit. Any ideas, what mistake, am I committing? any additional set up required?

const char string1[] = { "Hello World\r\n" };
unsigned int i;

void main(void)
{
  
  
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  BCSCTL1 = CALBC1_1MHZ;                    // Set DCO
  DCOCTL = CALDCO_1MHZ;
  P3SEL = 0x30;                             // P3.4,5 = USCI_A0 TXD/RXD
  UCA0CTL1 |= UCSSEL_2;                     // SMCLK
  UCA0BR0 = 104;                            // 1MHz 9600
  UCA0BR1 = 0;                              // 1MHz 9600
  UCA0MCTL = UCBRS0;                        // Modulation UCBRSx = 1
  UCA0CTL1 &= ~UCSWRST;                     // **Initialize USCI state machine**
  IE2 |= UCA0RXIE ;                          // Enable USCI_A0 RX interrupt + UCA0TXIE

  __bis_SR_register(LPM0_bits + GIE);       // Enter LPM0, interrupts enabled
 
}

#pragma vector=USCIAB0TX_VECTOR
__interrupt void USCI0TX_ISR(void)
{
  UCA0TXBUF = string1[i++];                 // TX next character

  if (i == sizeof string1 - 1)              // TX over?
    IE2 &= ~UCA0TXIE;                       // Disable USCI_A0 TX interrupt
}

#pragma vector=USCIAB0RX_VECTOR
__interrupt void USCI0RX_ISR(void)
{
  if (UCA0RXBUF == 'u')                     // 'u' received?
  {
    i = 0;
    IE2 |= UCA0TXIE;                        // Enable USCI_A0 TX interrupt
    UCA0TXBUF = string1[i++];
  }
}