The problem with D2k Forms or Designer 2k, is that the
Forms/desinger installer program doesn't accept
another ORACLE_HOME.
To fix the problem, you should first deinstall the
Oracle Software (Remove the Oracle key in regedit,
HKEY_LOCAL_MACHINE/SOFTWARE/ORACLE, the Oracle
directory (c:\orant\*.*) c:\program files\oracle and
the shorcuts in the menu (Start,Programs). After,
install FIRST the D2k Forms and/or Designer 2K,
setting the ORACLE_HOME to c:\orant\dev6i. When the
installation finished, install the Oracle 8i EE, and
set the ORACLE_HOME to c:\orant\ora8i. Remember, in
c:\orant\dev6i there are one tnsnames.ora for sqlplus
8.0 and other tnsnames.ora for sqlplus 3.0 (if you
install this product). In c:\orant\ora8i there is
other tnsnames.ora. Then you should to set up the
services in three tnsnames.ora.