Regarding sub site access, please follow the below step to provide full admin rights to the user account which you are using in our software:
- Please log in with Central administration URL through main Administrator account.
- Go to Site Action -> Site setting -> User permission -> on top panel we will able to see “Site collection Administration” .
- Now click on it and add the user which you currently using in our software on dialogue box and click on OK.
Please check and update us whether you are able to navigate sub sites from our software console after performing above step.
Alternate Solution : Please add the account to owner of the site collection and that fixed the permissions issue.