Can't compile a mxml due to component UniqueValueInfo is defined more than onces

[ShaningYu]

I created several customized widgets based ESRI Flexviewer.  They work well in FB 3.  Recently, I started to use FB 4, and some of them cannot be comipled any more (namely, the .swf can be created).  For instance, I got such an error as
component UniqueValueInfo is defined more than once in this namespace.  Remove the mapping to com.esri.ags.rederers.supportClass:UniqueValueInfo or com.esri.ags.rederers:UniqueValueInfo
Location  Unknown    Type: Flex Problem
In comparison with API 1.3, the com.esri.ags.rederers.supportClass waqs added in API 2.0.  How can this problem be solved?  I wish ESRI Flex Developer Team can provide the solution ASAP.

[ShaningYu]

I removed agslib-2.0 and re-used agslib-1.3, then it works fine.  I wish ESRI Flex Developer Team can solve the API's problem.

[ryanmordoff]

I just ran into the same problem when I rolled back to a previous svn revision.  The reason I got the error was because I had both the 1.3 swc and 2.0 swc in the project libs directory.  I removed the 1.3 and it compiled fine.  Did you have both 1.3 and 2.0 in the libs directory at the same time?