Can I create a Clover Report on Server A if I have the clover.db which I generated on Server B?

Yes you can if you use the command line options. You need to copy over your coverage.db and all the coverage.db* files that were generated.

However if you do not have the source files on your Server A, that you did have on your Server B you are going to get a number of the following errors

ERROR: C:/Applications/Confluence_STD/Source Code/confluence-2.9-source/confluence-project/confluence/src/test/java/com/atlassian/integrationtest/confluence/core/ (No such file or directory)

The report you generate will have all the coverage statistics but when you try and drill down to the class, you will get a error stating it cannot find the source file.

If you do have the source on Server A you can specify it using the -p option from Console reporter.