While trying to install any module in OpenERP I am getting the below mentioned error:

Integrity Error

The operation cannot be completed, probably due to the following: - deletion: you may be trying to delete a record while other records still reference it - creation/update: a mandatory field is not correctly set

[object with reference: Portal employee - hr.employee]

also, there is no install button for leave management, recruitment process, expense management, and employee appraisals. Can anyone please help us in sorting this issue?

Any help will deeply appreciated.

Thanking you,

Yuvraj Kumar