Hello Antonio,
What is the result of the below command?
/usr/sap/hostctrl/exe # ./saphostctrl -function ExecuteOperation -name versioninfo
Can you send the new error screen?
Are you using "/usr/sap/<SID>/SUM" folder for SUM?
I think you have checked the prererquisites under Update Guides 5.3 Starting the Software Update Manager chapter. But let me remind again also.
"
● Your system has at least the minimum supported SAP Host Agent version mentioned in SAP Note 2084104
on your remote SCS instance and on all additional application server instances, if your system has any.
● On the host where you want to start the UI, at least Java 6 must be installed.
"
Regards,
Yuksel AKCINAR