Are you still experiencing the decompression error? If so, please do the following within Impulse:
-Click the blue menu button in the upper left
-Choose 'Preferences...'
-Click the 'Reset Data' button
-Close impulse and relaunch it. You may notice a long update time, which is normal as it is rebuilding the deleted info.
Try the download again after ths. If you still have trouble, please contact support@stardock.com for further assistance.