XML Publisher doesn't generate output - java.lang.NumberFormatException: For input string: "."

XML Publisher doesn't generate output.
From log file:
+------------- 1) PUBLISH -------------+
Beginning post-processing of request 1718657 on node AUOHSGBLG04 at 07-SEP-2011 02:43:43.
Post-processing of request 1718657 failed at 07-SEP-2011 02:43:43 with the error message:
One or more post-processing actions failed. Consult the OPP service log for details.
+--------------------------------------+

From OPP log file:

Template code: XXPAY_AVAL_EXPRESS_XLS
Template app:  XXHR
Language:      en
Territory:     00
Output type:   EXCEL
[9/7/11 2:43:43 AM] [137229:RT1718657] Output file was found but is zero sized - Deleted
[9/7/11 2:43:43 AM] [UNEXPECTED] [137229:RT1718657] java.lang.NumberFormatException: For input string: "."
at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1224)
at java.lang.Double.valueOf(Double.java:475)
at oracle.apps.xdo.template.excel.render.BookDataWriter.copyCell(BookDataWriter.java:776)