reading clips in multithreaded environment

I keep getting this error when trying to read clip in multithreaded environment.

I keep reading clips at very fast pace .

It reads around 2000 and sometime more clips and then fails.

happening on call to FPTag.BlobReadPartial

It is in C# ,.NET enviroment.

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

at EMC.Centera.FPApi.SDK.FPTag_Close(FPTagRef inTag)

   at EMC.Centera.FPApi.Tag.Close(FPTagRef inTag)

   at EMC.Centera.SDK.FPTag.Close()

   at EMC.Centera.SDK.FPClip.Close()

   at EMC.Centera.SDK.FPObject.Dispose(Boolean disposing)

   at EMC.Centera.SDK.FPObject.Dispose()

Any help or pointers are appriciated.