Error -10215 with SDK 3.2 p5

Occasionally we get the FPLibraryException #-10215 while trying to open a pool in our production system.  When this happens we have to restart IIS or reboot the web server from which the FP SDK is called, and that seems to fix it, but it is not ideal, particularly during high usage.  I am trying to log extra information about the exception, but there doesn't seem to be any more information.  Example code:

If _defaultPool is Nothing

_defaultPool = New FPPool(_defaultCluster)

End If

Return True

Catch fex As FPLibraryException

LogError(fex, "CenteraResources" , fex.Message & ";" & fex.errorInfo.error() & ";" & fex.errorInfo.message() & ";" & fex.errorInfo.errorString())

Return False

End Try

There doesn't seem to be any info in the "errorMessage" property.  Here is what gets logged:

Exception of type 'EMC.Centera.FPTypes.FPLibraryException' was thrown.;-10215;;    at EMC.Centera.FPApi.SDK.CheckAndThrowError()     at EMC.Centera.FPApi.Pool.Open(String inPoolAddress)     at EMC.Centera.SDK.FPPool..ctor(String poolConnectionString)     at Mnet.GlobalDocs.CenteraResources.SaveFile(Boolean portlandFlag, Byte[] fileContent, String& clipID)

Can someone help us understand why we get this error randomly?

-VG