Final answer:
The filling error due to similar drug names and packaging could be primarily considered a human error, but it also suggests potential organizational issues in the systems for differentiating drugs. Manufacturing or technical errors would be less likely unless there were defects involved.
Step-by-step explanation:
The issue described appears to be a filing error that occurred because two different drugs had remarkably similar names and packaging. This would most likely be considered a human error at the root cause, as it involves a mistake made by the person responsible for filling the prescription.
However, we could also argue that this is an organizational issue if the systems in place do not adequately differentiate drugs with similar names and packaging. Organizational errors could stem from the company's failure to implement proper protocols to prevent such mistakes from happening. If there is a pattern of these errors, it could suggest a need for organizational change to prevent such occurrences.
Without additional context regarding the manufacturing and technical processes involved in the drug packaging, and assuming that there were no defects in making the drugs or their packaging, it seems less likely to classify the root cause as manufacturing or technical.