The package system of slackware doesn't seem to handle dependencies. THe error means, that xchat is trying to load a library it cannot find, but which is neede for xchat to run. These libraries sit in /lib, /usr/lib and /usr/local/lib. If the library is on your hd, then just run ldconfig (as root). Make sure that the path to the library is lited in the file /etc/ld.so.conf. If the library is not on your hd, you have to install it from your slackware cd. A search on google revealed, that libgmodule is in the package "glib-xxx". To install the library, do the following:
- mount the cdrom
- cd into <path_to_cdrom>/slackware/l
- run pkgtool (as root)
- select current
don't install anything until you find glib. If xchat wouldn't run after, run ldconfig and all should be well.