asset class block in only one chart level

I try to create one asset, but hits below error:

Chart of depreciation MS01 blocked in class Z01 (Use another class)

Message no. AA290

Diagnosis

The chart of depreciation MS01 is blocked in class Z01.

System Response

You cannot create assets using class Z01 in this company code.

Procedure

1. Use another asset class
2. Check whether the chart of depreciation is correctly allocated to    the company code
3. Check whether it is right to block the chart of depreciation MS01

   in class Z01

chart of dep is correctly allocated to that company code, I check oaoa, no lock indicator, how it is blocked