|I see that camera use Compact Flash cards. Are you sure that you are putting them in the right way round? Check the manual to see which way they should be inserted. CF cards are keyed and cannot be inserted fully the wrong way round (to prevent damage). Also, they need slight additional pressure for the final part of the insert to reset the eject mechanism. But don't push too hard if there's an obvious obstruction!|
If all else fails, take it to a camera shop rather than risking damage.