Problem in performing LOOCV

I am trying to run LOOCV on my regression model. I tried to run it in r and encountered the following warning message:

Warning message in y - yhat:
"longer object length is not a multiple of shorter object length”

This is my model:

x=glm(x,data = full_data)
mse_loocv=cv.glm(full_data,x)
mse_loocv$delta

Variables used in glm are:

x-
target_deathrate ~ avganncount + avgdeathsperyear + incidencerate + 
    medincome + popest2015 + povertypercent + studypercap + medianage + 
    medianagemale + medianagefemale + percentmarried + pctnohs18_24 + 
    pcths18_24 + pctbachdeg18_24 + pcths25_over + pctbachdeg25_over + 
    pctunemployed16_over + pctprivatecoverage + pctempprivcoverage + 
    pctpubliccoverage + pctpubliccoveragealone + pctwhite + pctblack + 
    pctasian + pctotherrace + pctmarriedhouseholds + birthrate + 
    Midwest + Northeast + South