tolson, I liked your suggestion of going to 1.6.7, so I removed 1.6.5 and installed 1.6.7. I also went through the User\AppData directories and removed any file that resembled anything like those normally installed in the "portable" folder.
For the 1.6.7 installation, I followed the Simblee Quick Start instructions explicitly, installing 1.6.7 by extracting from the .zip download, manually adding a "portable" folder, putting the "https://www.simblee.com/package_simblee166_index.json
" link in the preferences file, and loading the board (v1.0.2) with the Boards Manager. At the end of the process, I saw that all of the usual files were now in the "portable" folder and there was nothing in the arduino15 folder in ....Users\AppData. But, when I tried to run the Simblee Blink example, it compiled then gave exactly the same errors as before during uploading.
So...I tried some experiments. I deleted the contents of the "portable" folder and installed board version 1.0.1 using the Boards Manager. Same errors except "C:\...............Simblee\1.0.2" was replaced by "C:\............Simblee\1.0.1". Then I installed Arduino 1.6.7 on an old WinXP machine and went through the same steps above. I get exactly the same errors on that machine also.
It seems like I'm either systematically doing something wrong, or there is a bug in one of the files used during upload. The error messages make me think about formatting problems in strings used to generate file paths.
I should also mention that the fix suggested in ivo's earlier thread doesn't work for me here.