IMS online can't find my transaction ACB (CASTM5019E reason 1)

I'm trying to set up to test my IMS TM/DB system in Micro Focus Enterprise Developer. For the first transaction, I've genned the PSB & DBDs, imported the stage 1, defined the message regions, compiled the first program, started the transaction and databases. The problem is that when I enter the transaction on the screen (WIMLOGON), I get:

CASTM5019E IMS ACB WIMX0100 error; transaction WIMLOGON stopped, reason:  1

WIMX0100 is the PSB/program for transaction WIMLOGON.

The manual says reason1 is "ACB not found. The psbname.ACB file was not found."

But, I genned WIMX0100, and it is in the folder that ES_ACBLIB is pointing to. So why can't it find the ACB?

The configuration path is:

1. The acb is in the IMSGen under the VS Studio project
2. Project properties > IMS > Output Folders > Generated file path: .\\IMSGen
3. This sets $IDE_IMSGENPATH to path\\IMSGen
4. In ES Administration, IMS > General > ACB File Directory: $IDE_IMSGENPATH
5. This sets $ES_ACBLIB to path\\IMSGen