Error in creating new sample

[pierrepo]

While creating a new sample, I got an error message:

An error occurred accessing the database.

And the following output in console:

<model.Sample object at 0x7f36582cdd68>
<forms.UploadForm object at 0x7f36582cdf28>
chunk_numerotation could not be initialize. num_col and num_row missing
550 367
name 'chunks_numerotation' is not defined
An error occurred accessing the database.

@athenais, any idea?