Verify the Oracle Home's BIN directory is the first listing in the PATH Environmental Variable.
For XP:
a. Right click on My Computer and select Properties.
b. In the Advanced tab | click Environment Variables.
c. Under System Variables, highlight PATH and click Edit.
d. Move the Oracle home bin directory to the front of the entire path including the semicolon, if it is not listed first. If it is not there at all, you will need to add it. (Example: C:\app\user\product\11.2.0\client_1\bin;)
For Windows 7:
a. Right click on Computer and select Properties.
b. Click on "Advanced System Settings" on the left hand side of the window.
c. Click the Environment Variables button.
d. Under System Variables, highlight PATH and click Edit.
e. Move the Oracle home bin directory to the front of the entire path including the semicolon, if it is not listed first. If it is not there at all, you will need to add it. (Example: C:\app\user\product\11.2.0\client_1\bin;)
