There is a very nasty bug in LyX 1.2.2 configure script: if you configure as root and an error occurs during the configure step (e.g. xforms not found), the the script will delete the /dev/null device. This undoubtly leads to very bad effect, since /dev/null is a very basic device in any unix system.
If you have been victim of this problem, please complain here and I'll try to find out how to reconstruct it (some magic command that I do not know yet). I plan to release a 1.2.3 version that does not have this problem very soon. The same problem occurs in 1.3.0cvs (and 1.3.0pre1 I guess) but is fixed now in cvs. A bit of background: there has been for a long time some code in LyX configure script that removed the config.cache file (that keep tracks of tests results) when an error has occured. This allows to re-run the script once you have made correction without seeing the old results. However, starting with autoconf 2.5x, the cache file now defaults to /dev/null (i.e. no cache). Since LyX 1.2.2 was the first version distributed with an autoconf script generated with autoconf 2.52, this triggered this awful behaviour. Sorry for the problems that this may cause to your systems... JMarc