EXP-00003: no storage definition found for segment(xx, xx)

This error may occur while exporting table with LOB columns or large tables expanding to multiple extents.

Resolution: Make sure that the version of your export client matches or greater than database version.

You will get this error when export client version is lower than database version.

Example: Exporting 9.2.08 database with 9.2.0.1 client.