Can't build the compiler from within Flash Builder 4

Hey!

I've decided to try and dabble some with modifying the compiler, mainly just for fun but if I can I hope to be able to contribute to the project somehow. In any case, I've gotten everything to build properly using the ant script, but I can't seem to make the java compiler bits to build correctly in Flash Builder. This baffles me because everything seems to be set correctly and I get no linked resource errors. FLEX_SDK is set and verfied, as is ANT17_JAR, ANT_HOME and JAVA_HOME. Again, the project builds just fine using the ant script. What am I doing wrong here?

I get a ton (653 to be exact) of compiler errors. Here's a few just to get you an idea of what I'm talking about:

app.beginLine cannot be resolved or is not a field InterfaceCompiler.java /flex-compiler/src/flex2/compiler/mxml line 665 Java Problem

app.beginLine cannot be resolved or is not a field InterfaceCompiler.java /flex-compiler/src/flex2/compiler/mxml line 682 Java Problem

app.beginLine cannot be resolved or is not a field InterfaceCompiler.java /flex-compiler/src/flex2/compiler/mxml line 686 Java Problem

app.beginLine cannot be resolved or is not a field InterfaceCompiler.java /flex-compiler/src/flex2/compiler/mxml line 724 Java Problem

app.beginLine cannot be resolved or is not a field InterfaceCompiler.java /flex-compiler/src/flex2/compiler/mxml line 730 Java Problem

app.beginLine cannot be resolved or is not a field InterfaceCompiler.java /flex-compiler/src/flex2/compiler/mxml line 735 Java Problem

app.beginLine cannot be resolved or is not a field InterfaceCompiler.java /flex-compiler/src/flex2/compiler/mxml line 738 Java Problem

app.image cannot be resolved or is not a field InterfaceCompiler.java /flex-compiler/src/flex2/compiler/mxml line 686 Java Problem

beginLine cannot be resolved Element.java /flex-compiler/src/flex2/compiler/mxml line 131 Java Problem

beginLine cannot be resolved Element.java /flex-compiler/src/flex2/compiler/mxml line 142 Java Problem

beginLine cannot be resolved Element.java /flex-compiler/src/flex2/compiler/mxml line 151 Java Problem

beginLine cannot be resolved Element.java /flex-compiler/src/flex2/compiler/mxml line 162 Java Problem

beginLine cannot be resolved Node.java /flex-compiler/src/flex2/compiler/mxml/dom line 55 Java Problem

beginLine cannot be resolved or is not a field AbstractBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 762 Java Problem

beginLine cannot be resolved or is not a field AbstractBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 836 Java Problem

beginLine cannot be resolved or is not a field AbstractBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 945 Java Problem

beginLine cannot be resolved or is not a field AbstractBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 953 Java Problem

cdata.beginLine cannot be resolved or is not a field AbstractBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 751 Java Problem

cdata.beginLine cannot be resolved or is not a field AbstractBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 793 Java Problem

cdata.beginLine cannot be resolved or is not a field AbstractBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 825 Java Problem

cdata.beginLine cannot be resolved or is not a field AbstractBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 871 Java Problem

cdata.beginLine cannot be resolved or is not a field AnonymousObjectGraphBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 59 Java Problem

cdata.beginLine cannot be resolved or is not a field AnonymousObjectGraphBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 85 Java Problem

cdata.beginLine cannot be resolved or is not a field ArrayBuilder.java /flex-compiler/src/flex2/compiler/mxml/builder line 104 Java Problem

[ remaining errors snipped ... ]