Flash source editing problem

Hello.

I am having a problem with a flash source that I am editing: the Flash program moves very slow, it takes about 4-5 seconds to recognize that I have made a click or a selection.

It is not all the time like this. When I open the source, it moves ok for a while but after a short time it becomes impossible to edit. When I try to make a selection, edit the library or even write a word in ActionScript, it takes 5 seconds to recognize that I am making this (during this period, the cursor turns to the loading state).

Have you had this problem ? What could cause this ? Could the flash source be damaged ? Or could this be caused by my computer ? I should mention that I do not have any problem at all with my other flash sources.

One other thing that I should mention is that the flash source (a site that I am editing for a client) has about 14 mb in file size and the way that it is coded is not exactly efficient, far from it. Could this cause it ?

One last thing to mention is that I have about 70 mb of free space on the drive on which I am running the Flash program from.

The flash file is a Flash 8 format. I tried editing it using both Flash 8 and Flash CS3 but I have the same problem.

Please let me know what you think about this problem.

Thank you.