Context : The search for planets orbiting metal-poor stars is of uttermost importance for our understanding of the planet formation models .
However , no dedicated searches have been conducted so far for very low mass planets orbiting such objects .
Only a few cases of low mass planets orbiting metal-poor stars are thus known .
Amongst these , HD 41248 is a metal-poor , solar-type star on which a resonant pair of super-Earth like planets has been announced .
This detection was based on 62 radial velocity measurements obtained with the HARPS spectrograph ( public data ) .

Aims : In the present paper we present a new planet search program that is using the HARPS spectrograph to search for Neptunes and Super-Earths orbiting a sample of metal-poor FGK dwarfs .
We then present a detailed analysis of an additional 162 radial velocity measurements of HD 41248 , obtained within this program , with the goal of confirming the existence of the proposed planetary system .

Methods : We analyzed the precise radial velocities , obtained with the HARPS spectrograph , together with several stellar activity diagnostics and line profile indicators .

Results : A careful analysis shows no evidence for the planetary system previously announced .
One of the signals , with a period of \sim 25 days , is shown to be related to the rotational period of the star , and is clearly seen in some of the activity proxies .
The remaining signal ( P \sim 18 days ) could not be convincingly retrieved in the new data set .

Conclusions : We discuss possible causes for the complex ( evolving ) signals observed in the data of HD 41248 , proposing that they may be explained by the appearance and disappearance of active regions on the surface of a star with strong differential rotation , or by a combination of the sparse data sampling and active region evolution .