Problem in FORMS 6i Development

I have been getting an error while developing a form in D2K using Forms 6i. There are 2 base blocks. When I select an item in the first block, the details if the item gets posted in the second block. Then instead of using the key board if I use the mouse to scroll the first block, the when-validate-record of the second block gets fired and in this case raises an alert if there is no stock for the selected item. After I respond to the alert the system just hangs and the following has been written in the error file . I am not able to do anything because stock check has to be done compulsorily .
Please HELP!
[09/25/06 11:08:28 Pacific Standard Time]::Client Status [ConnId=0, PID=1192]
>> ERROR: Abnormal termination, Error Code: C0000005 ACCESS_VIOLATION

======================= STACK DUMP =======================

Fault address: 5DF0503B 01:0001403B
Module: C:\orant\bin\ifrd60.dll

System Information:
Operating System: Windows NT Version 5.1 Build 2600 Service Pack 2
Command line: IFDBG60 -SsL09@
FORM/BLOCK/FIELD: HOLD_OPD_ENTRY:THOLD_OPD_PRESCRIP.BUTTON_DRUG
Last Trigger: WHEN-VALIDATE-RECORD - (In Progress)
Msg: <NULL>
Last Builtin: SHOW_ALERT - (Successfully Completed)

Registers:
EAX:03FE8F48
EBX:03FE8F48
ECX:00010080
EDX:00040203
ESI:00000001
EDI:03FE8F48
CS:EIP:001B:5DF0503B
SS:ESP:0023:0012E34C EBP:00040202
DS:0023 ES:0023 FS:003B GS:0000
Flags:00010203


Call stack:
Address Frame
5DF0503B 00040202 ifzcal