That does not fix the problem.
While logged in and in the admin section, I was able to remain there (but I was not able to get back there from another page, which was how I realized the existence of the problem while remaining in the admin section). This enabled me to actually properly uninstall the plugin. I did so, and the problem was not solved.
I tried reinstalling to look for changes the plugin made. No luck. So then I tried manually deleting the folder from my FTP. No luck.
I have tried disabling all plugins. No luck.
The problem seemed to appear after I changed the base page for Anspress. Is there anything that might have been changed in my database, wp-config (can't find changes there), .htaccess (can't find any changes there) or other files?