Problem with suddenly aborting On-Line engine

Hi, we're running INFORMIX On-Line 4.0 at our site that we access primarily using the ESQL/C-Interface. After every first or second execution of our application the database enginge aborts giving the following error codes and messages: SQLCODE # -529 = Cannot attach to shared memory. ISAM-ERROR # -123 = ISAM error: no shared memory. The logfile contains the following entries: ... 15:21:45 On-Line Mode 15:28:29 Cannot Open Primary Chunk '/dev/informixrawdev1' 15:28:29 I/O error, Primary Chunk '/dev/informixrawdev1' -- Offline 15:28:29 I/O lseek() chunk 1, pagenum 1424, pagecnt 1 --> errno = 9 15:28:29 error on log write, buf 550000, physaddr 1050000, npages 1 15:28:29 Log Error - INFORMIX-OnLine Must abort 15:28:30 INFORMIX-OnLine entering ABORT mode!!! 15:28:32 INFORMIX-OnLine Stopped ... /dev/informixrawdev1 is a symbolic link to the actual disc partition we use as the raw device. I haven't got any clue as to the source of this problem. The machine we use for the engine is heavily loaded, but I don't see how this could have an effect on the engine accessing its raw devices. If anyone of you had similar trouble or knows about a solution please e-mail to peterh@prz.tu-berlin.de Any help is appreciated. Thanks Peter --- Peter Hofmann, Technical University Berlin