Getting error message "The text content of an invalid character was found" when using SQL Editor (61150)

Getting error message below when using SQL Editor:

The text content of an invalid character was found.
Line:_465
<SqlTemplate Description=-- W.
2.7 ID : 65A6
2.8 Count : 1
2.9 Status : New

This error also appears when loading a script or package.

RESOLUTION

1] Close Toad
2] Go to C:\Documents and Settings\<your user>\Application Data\Quest Software\Toad for Oracle\10.0\
3] Rename the User Files folder to User FilesOld
4] Open Toad
5] Follow the Wizard
6] Re-test the issue

Note: After renaming the User Files folder you will lose your settings.
If you want to recover some of them, please contact Quest Support