Internal heap ERROR 17177 addr=0x0

The message below is from my oracle database.
I don't know why this message is occured.

I programmed usging proc on IRIX 6.5 and Oracle 8.1.7.0.

The application that I programmed is constist of many processes.
Each process opens a session when the process starts up.
The code below is the code for open a session for a process.

if(oracleConnectedFlag==FALSE){
EXEC SQL CONNECT :username IDENTIFIED BY :userpasswd AT :db_name USING :db_string;
oracleConnectedFlag = TRUE;
}

when I commit or rollback I used code below
EXEC SQL AT :db_name COMMIT;
or
EXEC SQL AT :db_name ROLLBACK;

Sometimes it works well but sometimes it generates below error message.

What is wrong?

Please Help Me!!

Tanki95

********** Internal heap ERROR 17177 addr=0x0 *********


******************************************************
HEAP DUMP heap name="Alloc statemen" desc=0x1021f578
extent sz=0x1040 alt=32767 het=32767 rec=0 flg=2 opc=2
parent=101d63c8 owner=0 nex=0 xsz=0xfd0
EXTENT 0
Chunk 10221470 sz= 4032 free " "
EXTENT 1
Chunk 10220400 sz= 3952 free " "
Chunk 10221370 sz= 112 freeable assoc with mark prv=0 nxt=0
Chunk 102213e0 sz= 80 freeable assoc with mark prv=0 nxt=0
EXTENT 2
Chunk 1021e688 sz= 2448 perm "perm " alo=32
Total heap size = 10624
FREE LISTS:
Bucket 0 size=288
Bucket 1 size=544
Bucket 2 size=1056
Chunk 10220400 sz= 3952 free " "
Chunk 10221470 sz= 4032 free " "
Total free space = 7984
UNPINNED RECREATABLE CHUNKS (lru first):
PERMANENT CHUNKS:
Chunk 1021e688 sz= 2448 perm "perm " alo=32
Permanent space = 2448
******************************************************
Hla: 0