In general when trying a new package (which package are you trying ?)
I would use an example in the documentation, to understand how it should work, and 'prove' the package to myself, before trying my own data on it. This might allow for comparisons between the documented examples and your inputs.
If there is some deep fault in the package, and it is reproducible, contacting the package author to report a bug is often the way to go; and in the meantime, look for other alternative packages.
OK I tried open some other similar file which worked. So perhaps the error is in the file I'm trying to open for my assignment. But it has worked for others so IDK.