Question
why does the plant give off a sap-like substance that get on the table on which the pot sits on?

Answer
When small insects feed they give off this substance, check real close at the underside of the fronds and see if there is a mite or whitefly larvae problem; the palm itself doesn't have a secretion (as do some plants), so its got to be an insect problem. Spray the undersides of the fronds with normal Isopropyl Alcohol, this will take care of the problem, let it sit for about 6 hours then take it outside and spray it down with your hose to wash off all the residual alcohol and dead insects. Nick