I installed Erwin DM on Windows7 64-bit and cannot connect to Oracle. - CA Technologies ERwin Knowledge Base
Article ID: 377
Last updated: 11 Apr, 2012
:ERwin Data Modeler: 7.3, 8.0
Last Modified Date: 05/13/2011
Title: I installed Erwin DM on Windows7 64-bit and cannot connect to Oracle.
After installing the Erwin DM software version 7.3 or R8 on Windows7 64-bit you could encounter the error "Unable to locate client connectivity software ora7nt.dll" when trying to connect to an Oracle 9/10/11 instance (either for Reverse Engineering or because ModelMart is hosted on Oracle).
The reason for this error is that the Erwin application cannot find the required Oracle client in order to connect to the Oracle instance.
The Oracle client version that is supported on Windows7 64bit is Oracle 11g 11.2 R2 and it comes as 32-bit and 64-bit versions. Normally you would try to install the 64-bit client, but in this case you would then encounter the above error. Erwin DM is a 32bit application and requires 32-bit client libraries to make a successful connection.
To resolve the above error you would need to remove the 64-bit Oracle client (if already installed), reboot the machine and install the 32-bit Oracle client. It would be preferable to install the client into a directory that does not contain any spaces in the PATH (for example C:\app\Administrator\Oracle). It is not sufficient to install the Instant client software that is available from Oracle.
Also please review the following Knowledge document regarding the installation of Erwin DM on Windows7: