This may be the effect of sandbox mode (StrReverse function is also included), see the following knowledge base

To help enhance data security, you can choose to run Access in sandbox mode 2003. In sandbox mode, Access evaluates only those safe expressions in field properties and controls. An expression is considered safe if it does not use functions or properties that a malicious user could use to access drives, files, or other resources to which they are not authorized. For example, the functions Kill and Shell can be used to damage data and files on your computer and, therefore, are considered unsafe. Expressions that call these functions or properties will result in error messages when running Access in sandbox mode.

For a list of functions and properties that are blocked in sandbox mode, see Blocked functions and properties in sandbox mode.

Note Sandbox mode does not affect Visual Basic for Applications (VBA) code in files. Digitally signed code will run regardless of whether Access is in sandbox mode, even if it contains disabled functions or properties. Unsafe functions and properties are disabled only in expressions such as default values, control sources, or SQL statements.

Use Microsoft Jet Expression Service to implement sandbox mode to evaluate expressions. Microsoft Jet 4.0 Service Pack 8 (SP8) or later allows Access to be fully functional while also enabling Jet to disable unsafe expressions by enabling sandbox mode. However, the Jet Expression Service is not part of Access. You need to download and install Microsoft Jet 4.0 Service Pack 8 (SP8) or later to enable sandbox mode.

Notes Important Windows Updates include Jet 4.0 SP 8, so installing all Important Windows Updates will automatically install the latest version of Jet on your computer.

Important Installing the latest version of Jet does not automatically enable sandbox mode. When you start Access after installing a service pack or critical Windows update, you will be prompted to disable unsafe expressions. Clicking Yes will turn on sandbox mode and prevent unsafe expressions from being evaluated.

If you enable sandbox mode without having Jet 4.0 SP 8 or higher installed, some features will not work. For example, the wizard will not start, and you will see the following message: "This feature is not installed or has been disabled."

The wizard may not have started.

Switchboards created using the Switchboard Manager will not work properly.

You cannot use the RunCode macro action to call a Visual Basic for Applications (VBA) procedure.

Event handlers that call VBA procedures will not work correctly.

VBA procedures called in property pages or used in SQL statements will not work correctly.

The following VBA functions will not work properly when called from a property page; this is also true when they are used in SQL statements:

FormatCurrency

FormatDateTime < /p>

FormatNumber

FormatPercent

InStrB

InStrRev

MonthName

Replace

StrReverse

WeekDayName

For more information about installing the latest version of Jet, see About Microsoft Jet 4.0 SP8 or later (in English). For more information about enabling sandbox mode and to learn about the limitations and workarounds of sandbox mode, see FAQ about Access security warnings (in English).

For more information about sandbox mode in earlier versions of Jet, see the following Knowledge Base article: ACC2002: Jet 4.0 Expression can execute unsafe Visual Basic for Applications functions.

Solution: refer to the English instructions

\\HKEY_LOCAL_MACHINE\Software\Microsoft\Jet\4.0\engines\SandboxMode

0 Sandbox mode is disabled at all times .

1 Sandbox mode is used for Access applications, but not for non-Access Applications.

2 Sandbox mode is used for non-Access applications, but not for Access Applications. This is the default value.

3 Sandbox mode is used at all times.