CAUSE
This problem may occur if all the following conditions are true:
Your data source is not located on your computer–for example, the data source is located on a network drive. Your data source is a text-based file, such as *.txt. Your local intranet security settings in Microsoft Internet Explorer do not trust the location that contains your mail merge data source.WORKAROUND
To work around this problem, use one of the following methods.
Method 1: Trust the location in Internet Explorer To trust the location where your data source is located on your intranet, follow these steps:
Start Internet Explorer. On the Tools menu, click Internet Options. On the Security tab, click Local intranet, and then click Sites. In the Local intranet dialog box, click to select each of the three following check boxes as appropriate, and then click OK:
Include all local (intranet) sites not listed in other zones. Include all sites that bypass the proxy server. Include all network paths (UNCs).
*Note If your data source is in a location that is not covered by any one of these three check boxes, click Advanced, and then add the Web site that contains your data source. - Click OK to close the Local intranet dialog box. - Click OK to close the Internet Options** dialog box.Method 2: Move the data source locally Move your data source to a local folder on your hard disk drive on your Windows Server 2003-based computer, and then attach your local data source to your mail merge main document.