Hi Marcel,
I have the same issue. I issued the a similar command.
frx copy-profile -filename \Storagepath\username.vhdx -username domain\username -dynamic 1 -verbose
Got the same error as you. What version of FSlogix did you use?
Exporting registry information
Export Profile registry data error: 0x00000001
Error copying profile (0x00000001): Incorrect function.