I have an app that runs as a vi file under LabVIEW 7 on both NT and XP without problems, once built into exe file it only runs under XP, if I try to use it on NT I get Error 3008 AUtomation Refnum Class Problem. The vi simply polls a SQL dBase using SQL connectivity vi's and dumps data to Excel 2000. Like I said the vi runs fine as source and Exe on XP but not NT, Any idea's. Additionally I have another app that uses Tree Ctrl in LV7 , runs fine as Vi but when built into EXE the tree ctrl does not populate, again data is being pulled from SQL.