What is a TOC reading, why doe my player reject all CD's?

We have a Sony Mini CDT-101 system. When inserting a CD the display reads TOC Reading and then ejects all discs; even those that have played succesfuly before and also still play on other units. I cannot find any information on this problem or what a TOC reading may mean. Any one have some information on this.

John Hagger
December 2008