I'm sorry, but I can not reproduce this error on my phone. Perhaps this is the lockscreen or theme fault. Check that the default theme also have this problem. If not try to logcat this problem after unlocking.
Look a few comments above regarding the answer to your question about the 2.3.9 mod. Andy is working hard to port MIUI v4. He can prepare his own version of this mod, but maybe not. Until then, you can use my version. It is based on Andys work and are not significantly different.
Because there are changes almost in every MIUI version in files where modifications are injected. In case of implementing some fixes by Xiaomi in frameworks or .apk's, we need to modify them after ROM deodexing and properly recompile one more time. CM is not changing framework in every week. MIUI mods are often ported from Cyanogenmod github but some of them, like eg ICS fancy rotation animation need to modify dozen (sic!) of .smali java files and this is pointless to do for every MIUI update. Especially since this particular mod can cause stability issues and bugs with displaying launcher and applications elements.
If there will be a stable version of GB MIUI (if ever) than we can concern a possibility to make Final Ultimate MIUI Mod. But until that time... take it, or leave it.
Mods are installed using the siam script (also supports EVO 3D) but in some cases (on some partition layouts) it might not work properly. Before installing, you may manually mount the system partition and then try to reinstall package.
We looked at this more than once
That would be the best solution. The XIAOMI team uses a great OTA update mechanism that allows the modification of binary files. In this way, the update can only contain fixes, and not whole files and OTA has only a few megabytes instead of dozens, or hundreds of megabytes as in the case of the deodexed roms of the rest of the world (UK, US, DE, CZ, AU, etc.).
But first, I know of no developer who has mastered the mechanism of OTA (the Chinese do not provide sources). Second, even if someone is know how to use it properly, due to rom deodexing the files size is changing each time (because of the different decompile and compile options, eg. compression) and binary OTA mechanism can not be used (From what I know, he uses the injection of code into a specific hex address.)
However, if you have any useful information about the original Xiaomi OTA system - let me know.