Here we go again. 😀
As you already know, the DWL-500 is actually a DWL-650 PC card (plus a PCI adapter), which is based on the Intersil Prism2 chipset. A lot of the cheap 802.11b clients use this chipset.
I'm not too familiar with Slackware, but from the looks of things, you've done the right basic steps to set up a wireless PC card device.
The low-toned "boop" after the high-toned "beep" means the PCMCIA subsystem attempted to load a driver for your PC card, and failed.
So the first step is to look in /var/log/messages to see what PCMCIA card services is reporting.
Based on that, we might get a bit further.
As I mentioned last time, the linux-wlan-ng drivers are the preferred drivers for Prism2 devices, but orinoco_cs should work as well.
If you want to PM or email me, go right ahead but I won't necessarily be any more responsive or helpful. It'd be easier to send files that way though, than to cut & paste into a thread here.