Hello skysurf99,
I recommend contacting Arm's technical support team directly on this, via the links in the menu at top of page (Support -> Open a support case).
Regards
Ronan
An "implicit declaration" means that you have failed to provide an explicit one; eg, a prototype - which is usually due to a missing header file.
skysurf99 said:The above code and both function calls compile fine with the ARM 6.6.2 compiler version
So, in that version, see where those things are getting declared.
Then look at the 6.6.1 version to see what's different ...