Which wallet client did you use (core, electrum, multibit), and maybe it would be good to also include the version number.
This program uses Qt version 4.8.4.
What program are you talking about?
The stated version of 4.8.4 makes no sence to me, do you mean 0.8.4?
OP should look at the Bitcoin core version dialog, not the Qt version. Qt it the (crappy IMHO) cross-platform application framework that the UI component is written in.
BTW core v0.12.1 is using Qt version 5.5.0 so this appears to be an older version.