Yes, SBT does use an environmental variable but it uses either "TEMP" or "TMP" and if neither exists, it will put temp files in the root of the SBT folder.

>Just a guess, but does SBT set the temp folder with a environment variable and this folder does not exist on the XP machines?
>
>>We are running SBT PRO ceries 5.0i on our network for a long time and have made a lot of changes.
>>It worked fine for us, but some of our users had Windows 98. Now we are in a process of replacing all Windows 98
>>with Windows XP computers and have a hard time with one part of SBT - Account Receivable (Creating and editing
>>of Invoices). Several times per day SBT crushes with error on sbtw.exe. I tried to duplicate this error on my development
>>environment, but it happens unexpectetly and does not give me any additional information.
>>May be somebody have heard about similar problems.
>>Help please!