If your serial number is for a different language than the installation language you select (for example, you purchased a German Creative Suite, but attempt to install it in English), you will get an invalid serial number error. Reinstall the product, choose the correct language, and enter the serial number when prompted.
The Creative Cloud Cleaner Tool is designed to run after you uninstall your Adobe application. Run the appropriate uninstaller to remove the application producing the invalid serial number error first, and then run the Creative Cloud Cleaner Tool.
Adobe Indesign Cs5.5 Serial Number Mac Prol
This should give you a 24-numbers encrypted serial number. You must then decrypt it (the "SoftKey Revealer" freeware for Windows has a decryption tool, you can also run it using wine on Linux and possibly Mac OS).
Another way to decrypt the serial number, as opposed to downloading freeware tainted by evil payloads (at least one download site for "Softkey Revealer" has taint) is to run a simple JavaScript function (copied from elsewhere, but tested and works): 2ff7e9595c