A search for squarks in R-parity violating supersymmetry is performed in e(
+)p collisions at HERA at a centre of mass energy of 300 GeV, using HI data
corresponding to an integrated luminosity of 37 pb(-1). The direct product
ion of single squarks of any generation in positron-quark fusion via a Yuka
wa coupling lambda' is considered, taking into account R-parity violating a
nd conserving decays of the squarks. No significant deviation from the Stan
dard Model expectation is found. The results are interpreted in terms of co
nstraints within the minimal Supersymmetric Standard Model (MSSM), the cons
trained MSSM and the minimal Supergravity model, and their sensitivity to t
he model parameters is studied in detail. For a Yukawa coupling of electrom
agnetic strength, squark masses below 260 GeV are excluded at 95% confidenc
e level in a large part of the parameter space. For a 100 times smaller cou
pling strength masses up to 182 GeV are excluded.