pub.storage lock issue

Hi Experts,
We are facing the below issues when trying to get the config value stored in a xml config file.
Error:
pub.storage:get com.wm.app.b2b.server.ServiceException: [B]Exception encountered trying to create shared lock for target/b,
exception(java.lang.StringIndexOutOfBoundsException: String index out of
range: -5)
and some times this issue
pub.storage:deleteStore com.wm.app.b2b.server.ServiceException: Cannot aquire the lock
IS details:
IS - 7.1.2
JDBC Adapter - Version 6.5 and Fixes applied are JDBC_6-5_Fix19 & JDBC_6-5_Fix21
Fixes:
IS_7-1-2_Core_Fix10
IS_7-1-2_FlatFile_Fix3
IS_7-1-2_XA_Fix2
IS_7-1-2_Flow_Fix2
IS_7-1-2_WebSvcsXML_Fix8
IS_7-1-2_SrvPrtcl_Fix8
IS_7-1-2_PkgMgmt_Fix1

Please let us know the cause of these issues and let us know how to fix this issue.

Regards,
Datta