"Unable to locate type definition" error on pub.schema.validate step

This is only occuring in our TEST environment but not in our DEV environment, so I am really puzzled. I am unable to replicate it in DEV in order to fix it.

The step is validating against a schema document.

This is the error:

DT-100
Unable to locate type definition

I tried to redeploy the existing version to TEST, but that did not help. Has anyone else seen this error? It’s in webMethods 7.1.

The code is exactly the same in DEV and TEST, I just had it deployed today. Still the error persists only in TEST.

Error from our logs:
errorMessage - Invalid message format ,/@versionID DT-100 Unable to locate type definition ,/@systemEnvironmentCode DT-100 Unable to locate type definition ,/core:App
licationArea/core:Sender/core:LogicalID DT-100 Unable to locate type definition ,/core:ApplicationArea/core:Sender/core:ComponentID DT-100 Unable to locate type defini
tion ,/core:ApplicationArea/core:Sender/core:TaskID DT-100 Unable to locate type definition ,/core:ApplicationArea/core:Sender/core:ReferenceID DT-100 Unable to locat
e type definition ,/core:ApplicationArea/core:CreationDateTime DT-100 Unable to locate type definition ,/core:ApplicationArea/core:BODID DT-100 Unable to locate type
definition ,/tlg:DataArea/tlg:Sync/core:ActionCriteria[0]/core:ActionExpression[0]/*body DT-100 Unable to locate type definition ,/tlg:DataArea/tlg:Sync/core:ActionCr
iteria[0]/core:ActionExpression[0]/@actionCode DT-100 Unable to locate type definition ,/tlg:DataArea/tlg:Sync/core:ActionCriteria[0]/core:ActionExpression[0]/@express
ionLanguage DT-100 Unable to locate type definition ,/tlg:DataArea/tlg:TLogTransaction[0]/tlg:TransactionSequenceNumber DT-100 Unable to locate type definition ,/tlg:
DataArea/tlg:TLogTransaction[0]/tlg:PCMSValueDue DT-100 Unable to locate type definition ,/tlg:DataArea/tlg:TLogTransaction[0]/tlg:TransactionDetailnformation/tlg:Cash
ierLoanTransactionDetail[0]/tlg:FinanceOptionCode DT-100 Unable to locate type definition

What methods Dev guide states about the error:

NV‐011 [ISC.0082.9012] Unable to locate type definition
Cause: A simple or complex type definition is not found.
It is possible that a dependent IS schema that contains
this type definition was removed from the IS Namespace.

For example, IS schema pub.schema.w3c:structures references
a type definition in pub.schema.w3c:datatypes. If you receive
this error, it is possible that pub.schema.w3c:datatypes was
removed.

Response: Check to make sure that all of the type
definitions referenced by the schema are present.

If you are still facing the issue, please post the test IS package

We were facing the same issue, and found out that our webMethods Document had references to a namespace from an old XSD we imported.
In fact, the document contained, among other subdocuments, a copy of the document webMethods generates when you import an XSD, which carries with it the references to types defined in the XSD.
We ran into the issue when we updated the XSD (deleted it and reimported newer version), with a different targetNamespace attribute (old one was XXXX, new one XXXX_r8). The document still had the old references using the old namespace, which didn’t have any corresponding XSD in the server anymore.
You can see these references in Developer when you select a field of the document, in the properties frame, for the “Content type” property. There is the name of the type, followed by the namespace between brackets. If you click the button next to it, you can see that the type is “not found”.
Correct the references and the error should go.