Indefinite PAI & PBO loop resulting in a dump

Hi,

I am facing a peculiar problem with a module pool program. The screen flow is going awry. After presenting the screen and user action, the control enters PAI and then returns to PBO. So far good,, but after PBO, instead of displaying the screen, the control is going into PAI. Could you please tell what the reason might be.

The transaction is SAP's standard tcode PA30 and I am trying to delimit IT0027. I am calling this from the Manager's desktop.

Thanks,

Sudarshan