There is currently an issue with both QuickOffice and Adobe Reader 2.5LE as no longer offered in Nokia Store:http://store.ovi.com/content/2556
Suggest that you raise this issue with http://support.quickoffice.com whom are very helpful.
Thought it was more a case of this issue being caused by "firmware on device containing a stub file from a previous installation of Quickoffice, which cannot be removed. This file doesn't allow the system to install newer versions of Quickoffice or Adobe Reader. At this time, there is no way to remove this file other than re-flash your device".
An alternative is Picsel SmartOffice which seems to be receiving favourable reviews with no such Belle issues.
Symbian specialist until 31/01/2013 with interests in Maemo & MeeGo but an aversion to Windows!