Java Database Connectivity (JDBC)

HI all
my requirement is to connect to the excel sheet using the jdbc odbc dsn and read the worksheets and get the data.
i have created the dsn using vb scripting
so when i click on a button. a dsn is created dynamically and the same dsn is passed as parameter to the system which will call a java program

the java program will us the dsn to connect to the excel sheet to read the data.

This is working fine
the problem is sometimes the following exception is raised.

java.sql.SQLException: [Microsoft][ODBC Excel Driver] Cannot open database '(unknown)'. It may not be a database that your application recognizes, or the file may be corrupt.
at sun.jdbc.odbc.JdbcOdbc.createSQLException(Unknown Source)
at sun.jdbc.odbc.JdbcOdbc.standardError(Unknown Source)
at sun.jdbc.odbc.JdbcOdbc.SQLDriverConnect(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcConnection.initialize(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.zt.ebiz.install.client.ExcelDriver.getConnection(ExcelDriver.java:290)
at com.zt.ebiz.install.client.ExcelDriver.getHostInfo(ExcelDriver.java:337)
at com.zt.ebiz.install.client.InstallClient.executeActions(InstallClient.java:188)
at com.zt.ebiz.install.client.InstallClient.main(InstallClient.java:123)

For this we are just restarting the system.
Again it works fine.
i would like to know the cause of this problem.

please help me in this

thanks
Vijay Sunder