I am going to explain an error of Oracle EBS R12 Forms.
The error is: FRM-10043:Cannot open file
I was incountering this error while compiling Oracle Form on EBS R12 Server by changing it on local machine using Forms Builder.
In my case, the problem was version mistake of Form Compiler.
The version of my EBS application was: R12.0.4
and the version of Forms Builder on which I was editing is: 11g
I tried using editing form in Oracle Forms Builder 12c but was same error.
Then I figured out my error and the error was:
Form Compiler version on EBS Server was: 10.0.1
so I downloaded Oracle Developer Suite 10g and then edited the form using this.
Then compiled it on server.
Now compiled and working.