According to Intuit, Error Code -6010, -100: “Your QuickBooks installation may have been modified. Try re-installing QuickBooks and then try again” indicates that either anti-virus software with a firewall function is interfering with the operation of QuickBooks or you’ve run a registry cleaner that has modified your Windows registry.
If the error message was caused by anti-virus software, the solution is to disable that software. If your registry has been modified by a registry cleaner, the solution is to perform a clean install of QuickBooks (an uninstall followed by a fresh installation). Of course, before uninstalling any program, be sure you have adequate backups of both your program and your data.
For more information on resolving this error, consult this Intuit knowledge base article.