Build Failed on iOS (iPhone)

[Idan]

I followed the steps needed to start debugging apps with my connected iPhone device. When I build my app it returns "FAILED.".

I get lots of "duplicate symbol" errors:

For example:

duplicate symbol _OBJC_CLASS_$_CDVFileTransferEntityLengthRequest in:
    /tmp/6939fcaba3b94848a40b01f0ca69fc2f/DerivedData/Cordova300/Build/Intermediates/Cordova300.build/Release-iphoneos/Cordova300.build/Objects-normal/armv7/CDVFileTransfer-84D38BCC81920C98.o
    /tmp/6939fcaba3b94848a40b01f0ca69fc2f/DerivedData/Cordova300/Build/Intermediates/Cordova300.build/Release-iphoneos/Cordova300.build/Objects-normal/armv7/CDVFileTransfer-D57B0ED020DAC164.o

and exceptions:

Server stack trace:
   at Telerik.BlackDragon.Common.Data.TargetResultDataExtensions.ThrowIfNotSuccessful(TargetResultData targetResultData)
   at Telerik.BlackDragon.Client.ProjectTypes.MobileCore.BuildManager.#u4d.#qb()

Exception rethrown at [0]:
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccess(Task task)
   at Telerik.BlackDragon.Client.ProjectTypes.MobileCore.BuildManager.#VAd.#qb()

Exception rethrown at [1]:
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccess(Task task)
   at #i4d.#bde.#Gee.#qb()

Exception rethrown at [2]:
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccess(Task task)
   at #i4d.#bde.#Bee.#qb()

Exception rethrown at [3]:
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccess(Task task)
   at #i4d.#bde.#Aee.#qb()

At the bottom of the log:

ld: 36 duplicate symbols for architecture armv7s
clang: error: linker command failed with exit code 1 (use -v to see invocation)

 My app worked on Android, but it returns error when built for iOS. I have no idea how to approach to solve the build issue and need your guidance. 

Thanks in advance.

[Idan]

I changed the Cordova version to 3.2 from 3.0 and not it built ok. I will do further testing, but it seems to work fine noe.