The newer version of glib was pulled from the VL 5.9 repo. I don't know who did that and I don't know why. If you installed it on another machine you still have it in your /home/ftp/pub/veclinux/packages directory. You can transfer it from that machine to your new machine and install it:
installpkg <package name>
I don't have a VL 5.9 machine any more (running 6.0 exclusively now) and I haven't found the source or build scripts for that version in any case. I try to avoid mucking about with core libraries -- my skills aren't strong enough that deep under the hood for me to trust myself.
Next time I chat with one of the core developers I'll mention the glib situation. No promises on the outcome, though.
eMachines EL-1300G desktop, 1.6GHz AMD Athlon 2650e CPU, 4GB RAM, nVidia GeForce 6150 SE video
CentOS 6.5 (will try VL64-7.1 soon)
Toshiba Satellite A135-S4727, Intel Pentium T2080 / 1.73 GHz, 2GB RAM, Intel GMA 950
HP Mini 110 netbook, 1.6GHz Intel Atom CPU, 2GB RAM, Intel 950 video, VL 7.1