unable to install the SIS file

Really? I thought we'll experience an installation error in this case. Cause two files at the same path from different packages (with different UID) couldn't exist.
EDIT:
oh, sorry. When files has different names you wouldn't have any problem...

Hi Vivek,
!: used for z-or C-drive accordingly where you select your application to be install.
its memory card or phone memory.
I think you want to know only this.

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Well actually I had not told you to do anything.

anyway resources are not handled that way the way you have put it (actually your information is so broken yet again). You are not reading the documents correctly.
On the left side is the source directory and the right side is the target on the phone (as rightly put by Khalid the '!' indicates that it could be phone memory or memory card. But anyway..if you check the docs you will find probably something like this(Again when I went back to check your message, i find another problem..winscw binary is for emulator..for device you might want to package whats under the gcce release directory.)
"C:\Symbian\9.1\S60_3rd\Epoc32\release\gcce\urel\abc.exe "  - "!:\sys\bin\abc.exe"

For resource it might look something like this
"C:\Symbian\9.1\S60_3rd\Epoc32\data\z\resource\APPS\xyz.RSC" - "!:\resource\apps\xyz.rsc"

Also be sure to put in your loczlised files and registration files.(For more details check documents or example pkg files)

Check the documents on how to write pkg file (Please read the documents very carefully..trust me, its not a waste of time)

srivvivek, is it possible that you are building your application using one SDK and trying to install the application on a device which supports a lower SDK ?

Check what SDK the device supports and build with the same.

Is it possible that your app is trying to access a feature which your device doesnt support? For that knowing what your app does..and matching it to the device features might help. have you tried it on other devices or just one device?