[Gretl-users] list command in a loop environment

Hi gretl community, I just tried to run a script which conducts an OLS estimation and ADF test based on a list of series. I am pretty sure that a while ago this worked fine. But now I receive the following error running a simple script as the one you find below: "? loop foreach i level Data types not conformable for operation" A similar script is the following: -------- list level = y yp r dp cf q q2 i debt_costs dulc poil debt_networth debt_equity loop foreach i level ols $i const endloop ----------------- Any ideas what the problem could be? Cheers, Artur