Javascript error shows 'Calendar' is undefined

IE throws Javascript error 'Calendar' is undefined and some of the date fields do not have the Calendar Icon. Mozilla Firefox does not throw the Javascript error, but the date fields suffer the same problem. For more detail, refer to screenshot below and IssueNavigator.png.

To replicate this problem in either IE8 or Mozilla Firefox:

1. change server's locale Hebrew(he_IL). Optionally, change the User's locale to Hebrew. But make sure to run JIRA using the user account.
2. start JIRA
3. create an Issue
4. the date field(eg:Due Date field) does not have the calendar icon
5. go to the Issue Navigator, the Javascript will be thrown. Some of the date field does not have the Calendar Icon.

This is not reproducable with JIRA 4.1.2. It also does not affecting JIRA 4.2.1 that is running on server with German Locale.