Several issues found when launching uxins/uxext simultaneously multiple times in background:
1. Either the following error is returned: Unable to open file: XXX.dta. Error!
2. Or the following one: Error in unzipping file.
3. Finally, in case the load is important, the temp folder ($U_TMP_PATH) is deleted so all the uxins commands will fail
Bug affecting Dollar Universe 6 until version 6.9.21
Workaround: launch sequentially the commands uxins / uxext.
Solution: Update to a fix version listed below or a newer version if available.
Version: 6.9.21 - Released 3th July 2018