Symptoms
Some fields are not populated when importing data from Excel. For example, the [Account], [Contact] fields remain unpopulated in leads, and the [Surname], [MiddleName] fields remain empty in contacts.
Cause
The problem can appear in versions 7.6.0.1400 and below, mainly for English localization. But it can also occur in Russion localization, if a user adds object fields with captions that match the names of already existing fields. Basically, this is the core of the issue: an object contains different fields, whose captions match. During import, bpm'online selects the first field and populates it with data. The other field remains unpopulated. A typical example is the "Lead" object in English localization: it contains the "Account name" (Account) field and the "Account" field.
Solution
The simplest way to solve the problem without attracting developers is to change the field captions in the object and the column names in the imported file to avoid matching names as described above.
The other option is upgrading bpm'online to a later version.