To close the loop I am reporting the solution to this problem. Mark checked my installation and found that the memory limit was too low at 64MB and recommended that I increased it to 128MB. A check with my ISP and instructions they provided lead me to add the following lines (one being a comment to remind to myself) into the wp-config.php file:
/** Change memory limit by AC Ekin */
define('WP_MEMORY_LIMIT', '128M');
Both plugins coexist happily now with no conflict.
Thank you Mark for your assistance. I have also reported this to Jetpack team.
Cemal
