Software alternative

[Rick1971]

is there a Linux (free) software alternative for editing CS3 or CS 4 .FLA files?

[vinutux]

No.............

One and ony hope is.........Ask for adobe to make a linux version

[Stochastic]

You could also ask Adobe to release their proprietary formats to an open source model. This would eventually allow software like GIMP to read those formats.

But essentially, NO. Now you're experiencing, first-hand, the poisonous effects of proprietary software; your artwork isn't transferable to an open system.