An unexpected disconnection has ocurred, Pixel shader compiler error.

Hi, I'm playing here since the open beta started, first days I hadn't any disconnection, could play fairly well with my Low-end computer and even completed the act 1 without DC's. Since the last patchs game has been crashing every 1 or 2 maps, first freezing screen with a later DC from the server saying that famous "An unexpected disconnection has ocurred." randomly inside maps.

I checked my client.txt in the logs folder, it says this:
[CRIT Client 3084] Cached pixel shader compile error. Some objects may not be drawn.

I have a Powercolor Radeon 3450 HD (The highest AGP x8 I have found, since my motherboard doesn't have any PCI slot) which goes with Pixel and Vertex shader 4.1. ¿Someone has this problem also or it is just cause my PC is low-end and need to wait for newer patchs/upgrade my pc?

Thanks a lot for reponse.