My installer has been working until a few days ago, now I get:
JInstaller::install: File '/home/john/public_html/tmp/install_4c578c96e449f/com_mycomponent/admin/site/controllers' does not exist.
I checked the zip file and everything looks ok, I changed file contents but not the file structure at all since the time it was working.
ZIP STRUCTURE
com_mycomponent.xml
admin
controllers
...rest of admin files
site
controllers
...rest of site files
In fact the folder
com_mycomponent/admin/site/controllers
does in face not exist, I don't know why it is looking for this folder.