Hey,
You're on the right track here with the difference between uncertainty and error as used in QCE physics.
Yep, you want high precision and high accuracy - this is often not the case for IA2 data so try not to stress about this to much!
E.g. in year 12 I did a projectile motion experiment using light gates to measure initial velocity. iirc I had 4 decimal places on my m/s data and when I plotted this I had tiny bars for my uncertainty but the trend was not reflective of what we know about projectile motion. My results had high precision but low accuracy.
What you want to do is describe this and explain the results you got. Greater error than uncertainty means that you can't simply attribute this variation in your data from the expected relationship to measurement. Consider extraneous variables that may have impacted the results and look to your observations to see if you can use this to explain outliers.
Remember that reliability is about getting the same results again - I don't think you should conclude that based on one data point.
How are you getting 0% uncertainty, is this rounding?
Hope this helps!