I recently upgraded to Flex4 SDK. Before that everything worked fine. After that, I had some compiler errors, and a quick research brought to me that I had to add

-static-link-runtime-shared-libraries=true

to the additional compiler options. Doing some more in depth research, I discovered that this isn’t neccessary with a newer version of FlashDevelop – and I can confirm: it’s true =)
After the update procedure, everything compiled fine in debug mode. In release mode, it compiled too, but I got a runtime error: “VerifyError: Error #1024: Stack underflow occurred”. Again, investigating this error on the web, I stumbled over http://bugs.adobe.com/jira/browse/ASC-2266. The piece of code causing this, looked like so:

conn = new LocalConnection();
conn.client = this;
conn.allowDomain('*');
try {
	conn.connect("_SchemaConnection");
} catch (error:ArgumentError) {
	trace("Can't connect to _SchemaConnection");
}

So as you can see, it’s not the same as in the link above. I started commenting out line by line, and then I discovered, that it was the trace call. Replacing it with a Logger call finally fixed the error:

Logger.print(this, "Can't connect to _SchemaConnection");

I guess we’ll just put that on the unsolved mysteries stack