For a cross-platform binary file format, take a look at Storable. In particular, the nstore() function to store data in network order as opposed to the machine's native byte order. It's core in all perl 5.8.x versions so you shouldn't have to build it yourself.

Even so, you don't have compilers? Well then, if you need compilers to do your job then your boss will need to get you compilers. You can't just wave a magic wand.

And so what if you don't have root? Your sysadmins will, and its their job to install stuff that users need, after checking that you really do need them. I can certainly understand why they wouldn't want to install compilers on live systems, but don't you have development machines? If not, why not? That's another thing that your boss should be providing if he wants you to do your job.