Fix some ambiguous method errors.
Fix some ambiguous method errors.

My compiler couldn't determine which version of valueOf() to use.
GCC 4.0 on Mac OS 10.6.8

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core