Did you mean: "when I am using the database by instant web publishing, I can't"?
If this is the script from the contact manager starter solution, the add note script is not IWP compatible. Open up the script and remove or disable any Freeze Window steps that are present.
A fairly recently acknowledged bug in FileMaker keeps any script run from an Instant Web Publishing session from working if it contains a Freeze Window step.
For More Information see: Creating Notes
This is one of many acknowledged bugs that can be found in the Known Bug List here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: http://www.4shared.com/file/8orL8apk/FMP_Bugs.html
Thank you! It fixed it.