I use the expression "&%[TEMP]" to get the value of the Windows environment variable TEMP in a GuiXT script, which is "C:\Documents and Settings\Administrator\Local Settings\Temp" on my PC. When I tested it, the string returned by GuiXT was "C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp" instead. Is this an error?

In addition to the usual name for each folder, Windows has a shortened folder name as well. It consists of substrings that are at most 8 characters long, a restriction that goes back to the days of MS-DOS.  You can use the short folder name at any place where you work with the long name. For the TEMP environment variable, Windows returns this short name.