mxmlc dont find classes at compiling

Hello,
I have succesfully compiled and packaged the "hello World" Apollo application from the command line, but when i try to compile an mxml with AS code which import any class ("import mx.containers.Panel", in this case), the compiler fails with a strange error message, mix of french and english (the operative system language is French) which seems to be the equivalent to:

:mrt: (1061) Call to a possibly undefined method _ through a reference with static type _.

it happens also with the rest of samples, never find the path to "mx" or "com.adobe" classes.
-how can I set the compiler so it find those classes?(like I use to do with matsc) I don't find any mxmlc option or tag in apollo-config.xml.
any clue would be really appreciated,
Guillermo.
(Apollo SDK on frenchie winXP)