Exception ao ler arquivo Excel - POI 3.8

Note: Recompile with -Xlint:deprecation for details.   
compile:   
org.apache.poi.POIXMLException: org.apache.poi.openxml4j.exceptions.InvalidFormatException: Package should contain a content type part [M1.13]   
        at org.apache.poi.util.PackageHelper.open(PackageHelper.java:41)   
        at org.apache.poi.xssf.usermodel.XSSFWorkbook.<init>(XSSFWorkbook.java:187)

O código: 

InputStream fsCMCIQ = new FileInputStream(fileCMCIQ); 

XSSFWorkbook wbCMCIQ = new XSSFWorkbook(fsCMCIQ); 

XSSFWorkbook wbRPD = new XSSFWorkbook(fileRPD);[code]