I believe this is an identified bug that has already been fixed for next CBSubs 1.3 release.

Workaround is to use file with list of userid (comma separated).

Strange, I've checked your import and it appears to be all digits. Have you tried adding a trailing "," at the end of the list of userids? Have you tried splitting the file into small files and doing the import in chunks?

When is 1.3 coming out?

When it's ready.

Well, I did spot some bugs in the userid list, but even after removing them I could not achieve the objective. When I click on import, the screen would go blank. Then I would look at the subs list and discover it only added 1 subscription - not all the users on the list.

Then your import is now working, but you need to break it up. You're running through several thousand lines of code performing thousands of operations to give each user a subscription. Then multiply that by 2,000 and it will crash any non-dedicated hosted site. You need to split it apart into 3-4 or more files.

So, I had to manually generate an sql script to insert almost 2,000 users into the subscriptions table using phpmyadmin. No easy task for me.

Never do this, you've just imported 2,000 failed subscriptions. CBSubs has a complex process for creating subscriptions for users. In addition to several issues you may cause by doing this absolutely none of your CBSubs integrations have fired. For example if you're using SQL Actions then none of the queries you supplied executed for your users. You must use the import tool to create those subscriptions properly.

I recommend deleting the imports you've done via database query and splitting your import file into several files as to not run into memory limit or timeout issues.