Since JRE 1.7.0 update 13 my java fx application via webstart throws this exception:

java.security.AccessControlException: access denied ("java.io.FilePermission" "D:\tmp" "read")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkRead(Unknown Source)
at java.io.File.exists(Unknown Source)

when trying to access the harddisk. I signed all jars and e. g. with JRE 1.7.0 update 11 it works.