If you have an older version of Developer 6i and try to connect to Database server 11g, connection fails with following error message
ORA-02248: invalid option for ALTER SESSION
To resolve this problem simply upgrade your Developer 6i release by applying a patch or by fresh installation. For example, when I first time encountered this problem, I was using Forms Builder 22.214.171.124.2. I removed my previous release and installed Developer release 126.96.36.199.0. After up-gradation I was able to connect to 11g server without further problem.
When I first time tried to run my form, Forms Builder 188.8.131.52.0 asked me to re-enter password. This is because 11g has new Case sensitive password feature. When I first time connected to Forms Builder, I supplied correct password which was in lower case. When I tried to run form, Forms Builder tried to connect to 11g server with upper case user and upper case password. This is default behavior of Forms builder. Similar problem occurred when I tried to call reports from Forms using RUN_PRODUCT() method.To resolve this problem either set database users passwords to upper case or issue following SQL command to disable case Sensitive password feature.
ALTER SYSTEM SET SEC_CASE_SENSITIVE_LOGON = FALSE SCOPE=BOTH;
Upgrading your Developer release will resolve you problem but you must remember that developer 6i with 11g is not a supported combination by oracle as support for Developer 6i has been dis-continued. Oracle recommends upgrading you developer to latest version like Oracle Developer Suite 10g or Forms 11g.