I have always ticked the "Last Download Location" in CCleaner to clear Opera portable's save dialogue box with no problems. That was previously when I installed Opera in C:\Program Files.
Now that I've recently reinstalled Windows 7, I installed Opera as a standard user account in a custom folder that I created (C:\Apps\Opera). I learned that CCleaner doesn't auto detect Opera unless I add this line at the end of the settings file (ccleaner.ini):
CustomLocation1=OPERA|C:\Apps\Opera\profile
All is fine except the "Last Download Location" doesn't appear when analyzing or running CCleaner.
CCleaner v4.03.4151 (64-bit, portable)
Opera v12.15 (64-bit, portable)
Windows 7 Home Premium x64