archive log format error....

[dguywill]

Hello All,
I am having an error that I am unable to get around.. It is:
ORA-00249 : Invalid archivelog format specifier '0'

The parameter value for that is the default one which is :
log_archive_format : %ORACLE_SID%%S.%T

Any help will be grately appreciated..

Thanks in advance,
Dee.