PIAPPLUSER getting locked frequently

Hi 2 All,

My PIAPPLUSER is getting locked very frequently...

Frankly , I don't know why..

When i unlocked it and tried to login into SLD using PIAPPLUSER i got this error message

"You do not have permission to view the System Landscape Directory. Minimum required: UME role with permission com.sap.lcr.LcrUser and J2EE role LcrUser. See the SLD Post-Installation Guide for details"

and i can't do anything in SLD. i can't enter in System Catalog as well as in S/W Catalog .

Waiting for valuable inputs...:-)