Flex builder 3 - clean build

Question

I am having problems with Flex builder 3 not building
correctly.
It does incremental builds - to reduce compilation time on
individual changes I assume - but quite often gets it wrong and
produces a whole stack of invalid errors.
I've tried the build clean function but that doesn't seem to
actually perform a full build clean. It only resolves these issues
some of the time. I can mess around with the code - deleting and
then un-deleting lines that are throwing up errors, or sometimes
renaming the main style sheet - which usually fixes it. But this is
a constant drain on my productivity and sometimes no amount of
messing around will help. In those cases only exporting the entire
code base and creating a new project resolves the issue. (I would
guess because this forces a completely clean build)
Does anyone know of a way to either eliminate this problem
alltogether or failing that perform a full clean build through the
builder.
I'm guessing a customised any build script may be the
solution, but I've never created one of these.

Answer 1

jfb, I tried all that but to no avail.
Devtron, am not using SVN ! I'm using the Flex Builder standalone version.
Thanks guys for your replies. I just ran out of patience and just started working with FB4 and all is going great !
Thanks again