Hello Ramu V,
The debug board LEDs are connected on the CPLD. Please refer to the pdk10_imx25_Hardware_UG.pdf and also the PDK schematics.
If you are using Redboot you can access the LEDs by using the "spi_cpld" command, try:
Redboot> spi_cpld 0x20000 0xff
That would lit all 8 LEDs.
The procedure is different on other i.MX PDKs where you had to write to CS5 to access the CPLD.
Hope this helps.
Best Regards,
Renato