First of all, if you are posting a question on one forum, stick to it. It's kind of rude to the community that you just provide a link to the question you posted somewhere (MSDN forum) else.
Anyway, what you need to understand is the installation of a WSP does not do much. It just makes sure that you relevant solution files are deployed to the SharePoint farm.
Next comes the point when you activate the features. It is when the code which you have written to "Activate" certain features for your custom solution.
Regarding the error you are getting, it typically means that you have more connections (default is I guess 100) open for a SQL database then you are allowed to.
If you have a custom database and you are opening a connection, make sure you close it as well.
Look at the similar discussion here:
The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached[
^]
I would suggest further to look at the
ULS logs[
^] to get better insight.