When you install InterBase 2009 Update3 on Windows and select the Server and Client install and not the Client only install, such as the following:

GDS32.DLL, which is the InterBase client library, does not get installed to Windows\System32. Depending on the access method you are using to connect to InterBase, this may cause a variety of different errors.

When connecting via the Data Direct ODBC driver, you will receive the error:

Specified driver could not be loaded due to system error 126 (Data Direct ODBC for InterBase).

When connecting via the Database Express (DBX) Driver with RAD Studio 2010, you will receve the error:

Cannot load GDS32.DLL library (error code 126). The GDS32.DLL library may be missing from the system path or you may have an incompatible version of the library installed.

When connecting via the InterBase Express (IBX) Driver with RAD Studio 2010, or the InterBase driver for Delphi for PHP you will receive the error:

InterBase library gds32.dll not found in the path. Please install InterBase to use this functionality.

When connecting via the Borland Database Engine (BDE), you will receive the error:

Vendor initialization fail.

Cannot load an IDAPI service library.

File: GDS32.DLL

Alias: …

There are a number of possible solutions to this problem.

1. Select the InterBase Client Only install when installing InterBase. This may be selected with the Server and Client install, or done separately.
2. Copy GDS32.DLL from the bin folder where InterBase is installed to the Windows\System32 directory.
3. Copy GDS32.DLL from the bin folder where InterBase is installed to the directory where your application that uses it resides.
4. Add the bin folder from where InterBase is installed to your path.