I am on a new PC and solve as follows:
*. Install an old version. I use: install_octoplus_FRP_1.7.1
*. Install from officiate website install_octoplus_FRP_1.8.6
*. When the error appears say ABORT
*. Open Octopus FRP and that's it! it is updated
Note: Octopus FRP said: "There is a silent update" I updated from the program and installed the update without problems.