ERROR en la libraria de un web services

Could not load file or assembly 'SuLibreriaLIB' or one of its dependencies. An attempt was made to load a program with an incorrect format.
  Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.



[BadImageFormatException: Could not load file or assembly 'SuLibreriaTransCashLIB' or one of its dependencies. An attempt was made to load a program with an incorrect format.]


Solucion: Compile nuevamente su libreria y coloquela en el web services y listo.

En los web services se debe verificar el Pool que esta utilizando  y debe colocar en True la propiedad Enable 32-Bit Applications