Movie clips not playing in swf

hi, i have 4 video clips in 4 differnt swf files. i call them to load into my moviePlayer.swf, they load and play just fine. all of this i call into my main swf by way of nav buttons it loads in my moviePlayer fine but when i go to play video clips by way of 1-4 buttons on my moviePlayer they don’t play, please help, i already searched forum but couldn’t find anything.