Problem in disableing fields in selectin screen

Hi all,

I have 2 radio buttons download and upload on the selection screen in one block,

2 fields p1 and p2 in another block,

2 fields p3 and p4 in another block.

initially the download button is checked and p3 and p4 are disabled and p1 and p2 are enabled.

when i select upload p1 and p2 should be disabled and the other 2 fields should be enabled.

The problem here is i have handled initial check for p1, so when i am selecting upload button it is giving the error message and the fields p3 and p4 are not getting enabled and p1 and p2 are not getting disabled.

Please someone let me know how to solve this.

thank you,

Dev