I've found that a lot of people have had issues getting OpenCL to work properly on ATI/AMD HD 4xxx series cards, because support for them was sort of an afterthought and they never had a full implementation in software. I was wondering if anyone was able to get it working properly; perhaps it takes a "special" mix of driver and SDK versions to hit the sweet spot. I've tried this a couple of times over the years with no real success to show. I currently have the latest Catalyst driver (13.9) installed, as well as SDK 2.9...

The following software versions are listed on the download page for Catalyst 13.9, when going through the AMD site to find the appropriate driver for my card and operating system, Windows 7 64-bit.
Display Driver ver. 8.97.100.11
OpenCL(tm) Driver 10.0.937.2
Catalyst Control Center 2013.0429.2312.39747

However, when I open the ATI control center after installation and check the "Information > Software" tab, no listing exists for OpenCL.

BOINC reports this: CAL: ATI GPU 0: ATI Radeon HD 4600 series (R730) (CAL version 1.4.1734, 1024MB, 992MB available, 960 GFLOPS peak)

In the interest of disclosure, this is only partially BOINC-related; it would be nice to have OpenCL working properly to maximize the number of BOINC GPU projects I can contribute towards, but I'm really trying to get it to work so I can give the whole Bitcoin mining thing a shot... At least, scrypt mining through middlecoin which pays out in BTC. Failing that, it will continue to crunch for the few BOINC projects that support it without OpenCL.

---

My Detailed BOINC Stats

I think your driver is too new. If I remember correctly, the HD4000 range had only OpenCL 1.0 beta support, and they've been deprecated a long time ago. Despite what it says on that page. It's been saying that blurb since 13.1, and you do not want 13.1 as those are borked.

So try 12.10 first. And if need be, work your way downwards, see the cheat sheet for older versions.

---