I was getting an error-message window from Windows XP Task Scheduler every time I started Windows, telling me that one of the schedule tasks failed. I tried to find which task in the Task Scheduler list, and they all ran (on accessing "run" from the mouse pulldown menu) except the two that ran RealUpgrade.exe (c) for RealPlayer.(c) Deleting these is no good, because RealPlayer puts them back; and the same error message recurs on the next Windows logon. I couldn't find any solution or even a discussion of the specific problem on an Internet search.
Going to McAfee Security Center (c) (version 2012) and navigating to "Firewall" then "Settings" then "Internet Settings for Programs", I found RealUpgrade and RealUpgrade Launcher set to "Full". I then set Net Guard to "off" in the RealUpgrade Launcher entry. This got rid of the error message on restart.
I have "Check for the most common threats during startup, for a fast startup time" checked (asserted) in the Real-Time Scanning settings, but I've previously tried asserting the "Check for all known threats during startup, for a regular startup time". I looked to verify that the "fast startup" was checked, and it was; and this was to be my next resetting if the Net Guard check I described above hadn't worked. I may try, alternatively, re-asserting Net Guard for RealUpgrade Launcher and asserting "Check for all known threats during startup...", but the unchecking of Net Guard for RealUpgrade Launcher has seemed to solve the immediate problem. If the alternative method works, it may be a safer solution: I don't know. Any opinions?
NetGuard is blocking a specific IP address (or more than one address) that your PC tries to connect to when these scheduled tasks run. Usually the Netguard block message says what that address is. Can you make a note of it and let me know what it is?
There is always the possibility that your RealPlayer installation has been modified by malware to connect to a malicious site. If I saw this on my PC I would uninstall RealPlayer and run scans with McAfee and Malwarebytes, then clean out any remaining RealPlayer files and registry settings using CCleaner (and a manual check of the file system) before re-installing RealPlayer from the Real.com site.