With version 2.3.4 compiled on OS X 10.8.2 and using LyX 2.0.6
Export of floats with graphics/tables paragraph formatted to "center" fails.
Default formatting (justified) exports floats correctly.
Also, noted an error in compiling,
the doc/latex2rtf.html does not get compiled and causes make install to fail (I copied doc/latex2rtf.txt to doc/latex2rtf.html as a workaround)
1.) "Export of floats with graphics/tables paragraph formatted to "center" fails.
Default formatting (justified) exports floats correctly.":
Could you please supply a minimal test example (LaTeX file) which exhibits the problem?
2.) "doc/latex2rtf.html does not get compiled" (in future, please open a separate ticket for each problem):
Works fine here (under cygwin as well as under Windows, provided that all programs required for compiling are installed).
What is the error message? Is "makeinfo" installed in your system?