Fix3 CVS tree is still not opened, thus I've updated my 680 based OpenOffice.org tree to SRC680_m23 and (almost) migrated our build system to it. The file filter/source/config/tools/utils/FileHelper.java in SRC680_m23 contains:
// __________ Imports __________
import java.io.*; import java.nio.channels.*; import java.lang.*; import java.net.*; import java.util.*;
java.nio.channels is JDK 1.4+ thing thus it broke 1.3 builds. Issue #i25034# filed to get it fixed.