The issue is exactly this: I am attempting to create a time lapse video using several different clips. All of this footage comes from the same camera. I'm aware that I must "convert entire clip" in order to be able to adjust the speed to my specifications. Half-way through this process, imovie began giving me the following error message: "This clip cannot be converted. Error -50". So now i sit with some of the clips converted and the others not. This applies to every clip and not just one specific. I am no longer able to convert any of my footage from any clip. This just randomly happened midway through converting the clips individually. Taking a look at the clip in quicktime's inspector, here is what is seen:

clip that has been converted:

clip that cannot be converted:

here is a snapshot of my quicktime codecs folder:

Additionally, when attempting to move rejected clips to trash nothing happens. At first attempt, it showed a progress bar and ironically, began to fill up my hard drive. the items never made it to my trash bin nor were they deleted. now, with each subsequent attempt, i click on the available icon only to have it depress for a moment, followed by nothing. the rejected clips remain. how can i get rid of them?

so, two issues id like to resolve really. any help on either is greatly appreciated.