Try using tex2lyx directly on your file by command-line, there should be a more precise error message, which you could again post here.I just installed Lyx 1.6.2 and attempted to import a .tex document but get the following error:"LyX: Cannot convert file. An error occurred while running tex2lyx -f 'main.tex' 'main.lyx".(The error message is my recollection and may not be exact.)
Kurt
Florian