Toad
Disable the 'Display large numbers in Scientific Notation' option in View | Options | Data Grids - Data the next time you connect to TOAD and view the Schema Browser | Tables | Data tab an OCI-22061: invalid format test [TM9] error is received.
WORKAROUND
Upgrading the Oracle client from version 8.0.5 or 8.0.6 to version 8.1.7 or greater will resolve this issue.
STATUS
Waiting Fix in a future release of TOAD.