Not able to change the valuation class

Dear All

I am not able to change the valuation class for a material in particular plant.

It is not split valuated

No stocks exist in this plant

But, when I click on 'display errors' (in MM02 transaction), it is showing some open POs for this plant for this material. But these are not open POs in real. I have confirm the same with ME2M for this material and plant selecting seleciton parameters as WE101. Here, i am getting message 'no suitable purchase documents found'.

What can be the cause of these open POs (which are not acutally open, as for full quantity GR and IR is done for all POs)?

Because of this error, I am not able to change the valuation class I suppose. Can you please help me out of this issue.

Thank you