How to make install faster after compile?

Try to use a real device instead of the emulator. If you are using the emulator then I recommend you to use Android 2.3.3 emulator.

The purpose of the designer scripts feature is to allow you to edit the UI without needing to compile and install each time.

Instead of 2.2 emulator I am using 2.3.3 now. But I am having one problem. After 2 activities display, when application enters the 3rd activity, which is having imageview, 2 panels, scrollviews, it shows "Unexpected error" popup. But same is working good with 2.2 emulator.

I tried to debug the code. But before coming into the activity create it shows the error popup. I am not able to figure out the problem. What may be the cause of this issue?

You should check the logs (right side of the IDE). If you do not see an error message then check the unfiltered logs. There must be an error message there.

Check the logs on the right hand side of the IDE. You might need to unfilter them to get access to the information you need.

Have you generated the code in debug?

I would seriously recommend looking at compressing the graphical elements that you have defined. I do a lot of work on my Apps to ensure that the PNGs and so on are made as small and compact as possible without compromising the quality. If the images are large, consider reducing the physical size of them, especially if the App is targetting phone users, they don't have that much screen real estate to play with anyway. I used a tool I've had for years, which I purchased to reduce the size of graphics files. It can reduce the number of colours for instance and allows me to reduce the pixel dimensions and jpeg compression and apply a further compression technique as well. It's called xatio, from xat.com but there are other tools, probably free ones around that are available. It can make a big difference to the APK size.

I figured out the problem.

If I keep the below line
"Max Application VM heap Size" = 24

in the hardware properties of emulator in AVD manager, then it throws error. But If I delete the above line, it works fine. This is the same case with emulator 2.2 and 2.3.3. I wonder how this parameter relates to this problem.

The unfiltered log will probably tell you.

Max Application VM heap Size

It's setting the Maximum Application Virtual Memory heap size, I guess without it it's set too low and you blow the limit.