RPG program halting with RNX1251 Permanent I/O error occurred in DISPLAY file

Hello

I have an RPG that displays a subfile.

After some user action, i call another program that has it's own DSPF. This
way there are 4 to 5 programs called with their own DSPF. And all screens
have been compiled with Restore display RSTDSP(*YES) attribute.

When control returns to my 1st program, I am displaying a WINDOW without
using any of these keywords CLRL, OVERLAY, PUTOVR, PUTRETAIN, ERRMSG, or
ERRMSGID.

But program fails with below message on EXFMT of the Window record format.
What do you suggest ?
This failure does not happen all the time. Happens sporadically.

The major return code is 80.

Message ID . . . . . . : RNX1251 Severity . . . . . . . : 99

Message type . . . . . : Escape



Message . . . . : Permanent I/O error occurred in file INPR410S.

Cause . . . . . : RPG procedure INPR410R in program PRODUCTION/INPR410R

detected a permanent (not recoverable) file, session, or device error.
The
session, device and/or program has been stopped. Examine the
major/minor
return code value to determine the specific error that occurred. If the

major return code is 80 then a system or file error occurred and
programmer
action is required to fix the problem.



*-------------------------------------------------------------------------
A R POPUPWIN
A WINDOW(13 3 10 72 *NOMSGLIN)
A WDWBORDER((*DSPATR RI) (*CHAR
' -
A '))

A MSGLIN01 70A 1 2COLOR(YLW)
A MSGLIN02 70A 2 2
A MSGLIN03 70A 3 2
A MSGLIN04 70A 4 2
A MSGLIN05 70A 5 2
A MSGLIN06 70A 6 2
A MSGLIN07 70A 7 2

A 10 2'Press ENTER to return.'
A COLOR(BLU)
A MSGLIN08 70A 8 2

*-------------------------------------------------------------------------
----
Regards,
Mohan Eashver