I've just installed the 9.1 COM+ version on a fresh XP virtual machine
I've saved the trial license.lic in the same folder as the EasyXLS.dll

I try the VB6 tutorial example and i received the error :

EasyXLS Professional for COM+ 9.1.0: EasyXLS license file is not valid!
Exception has been thrown by the target of an invocation.

Whats wrong?

Windows XP is an old operating system and it is out of support from Microsoft.
EasyXLS 9.1 uses the latest cryptographic algorithm for licensing.

EasyXLS 9.1 requires .NET Framework 4.0 or later. .NET Framework 4.0 works on Windows XP with SP3.
It is possible that RSA-SHA256 algorithm not to be present on your machine. In order to check this situation, see if rsaenh.dll 5.1.2600.7345 or later is present on C:\Windows\System32 folder.

I recommend you to install an older version of EasyXLS, that is more appropriate for your configuration:
https://www.easyxls.com/docs/EasyXLS_Trial_for_DotNET_v8_6_32bit.exe
Uninstall EasyXLS 9.1 and install EasyXLS 8.6.