I've been having issues with Market apps not being compatible ever since I have been playing around with both CM7.1 and Oxygen 2.3.2. Those same apps were working/compatible when I had Oxygen 2.2.1 running, but have not been able to load them from the market after installing both CM7.1 and Oxygen 2.3.2. After a bit off googling it sounds like it could be a pixel density issue. Although, to be honest, it sounds like the newer (v3.1.11) market versions are just being a lot pickier with resolutions, and won't even let you download an app if it detects even a hint of incompatibility. Argghh!!!
Anyway, I wonder if some kind person with a stock X5 U8800 ROM could do me a favour and have a look at their build.prop file (system/bulid.prop) using root explorer and tell me what their LCD density is set at.
Any help would be much appreciated! :)