Android Question ERROR Compilation of a game source code

Hello,

I have a source code of a game ,when i try to compile the code i receive the following error:

Error: Unable to access jarfile C:\Android\android-sdk\tools\..\platform-tools\lib\dx.jar
Optimized dexer failed. Switching to Standard dexer.

For other source code the compilation is OK.

I already checked the dx.jar existence , the jar exits in the android-sdk Folders.

Any Help!