glmer error (maxstephalfit) PIRLS step-halvings failed to reduce deviance in pwrssUpdate)

Hello
I am running a model on my data, and getting error message. Below is the script and the out put. Any ideas what the problem could be? I can share the data, if required.

b<-read.csv("clipboard",sep="\t")
attach(b)
modelb<-glmer(Biomass1~Habitat+Season + (1|Location/Replica), family=Gamma)

(bG) nan @ pos 12: y= 40.4; mu=-429094; mu inv=-2.33049e-006; wt=1; y/mu=-9.4152e-005; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-858187; mu inv=-1.16525e-006; wt=1; y/mu=-4.7076e-005; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-1.71637e+006; mu inv=-5.82624e-007; wt=1; y/mu=-2.3538e-005; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-3.43275e+006; mu inv=-2.91312e-007; wt=1; y/mu=-1.1769e-005; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-6.8655e+006; mu inv=-1.45656e-007; wt=1; y/mu=-5.8845e-006; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-1.3731e+007; mu inv=-7.28279e-008; wt=1; y/mu=-2.94225e-006; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-2.7462e+007; mu inv=-3.6414e-008; wt=1; y/mu=-1.47112e-006; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-5.4924e+007; mu inv=-1.8207e-008; wt=1; y/mu=-7.35562e-007; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-1.09848e+008; mu inv=-9.10349e-009; wt=1; y/mu=-3.67781e-007; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-2.19696e+008; mu inv=-4.55175e-009; wt=1; y/mu=-1.83891e-007; log(y/mu) =1.#QNAN
(bG) nan @ pos 12: y= 40.4; mu=-4.39392e+008; mu inv=-2.27587e-009; wt=1; y/mu=-9.19453e-008; log(y/mu) =1.#QNAN
Error: (maxstephalfit) PIRLS step-halvings failed to reduce deviance in pwrssUpdate
Thank you,
Moses