Here is a fix for the problem that you observed. I installed it. Thanks. That fixed the first problem, but not the second ("pushd: no other directory"). tex4ht-javahelp-xtpipes.tex did not have the necessary \input{tex4ht-dir} (maybe you had that as a local change). I committed that too.
By the way, when the same change is being done in several files, there's no need to repeat the description in the ChangeLog. Just * file1, * file2: change. suffices. I am a bit puzzled why I did not observed the same error. I've observed that often errors happen on run N that do not happen on run N+1. I don't usually try to clean everything before any given run. appropriate to disable it in the .tex by default unless do_java is ... That would be easy to do through the texh4t-dir.tex that could contain a switch passed from the makefile. If you want to make a patch for that, it's fine with me. I was just making the minimum change in the shortest possible time :). A bigger problem is that even after running make do_java=1 and everything succeeding, running make do_java=1 again still causes everything to be remade. That should not happen. I did not try to trace the dependencies with make -d or whatever, though ... Best, Karl