We encountered one issue after integration 10g iAS (IDM 1.4 + SSO) with our Oracle Application Instance 126.96.36.199. We were not able to change user password via form (FNDSCAUS). Navigation as follows Security > User > Define. Although we were able to change password via FNDPASS but not via form.
The problem lies in system profile "Application SSO LDAP Synchronization" (APPS_SSO_LDAP_SYNCH). We had this proble disabled at site level, which was causing the issue. After changing this profile at site level to value enabled it worked. So make sure you have this profile enable if you like to use standard feature of password change.
Happy Troubleshooting !!!