Latent class analysis in R

Question

I worked latent class analysis in R, and have two questions.

Question1; lca4-6 could analysis, but lca7 could'nt analysis.

lca7<- poLCA(f,LATENT,nclass=7, maxiter = 500, nrep = 100, graphs = TRUE)
summary(lca7$posterior, disits=2) 

Error in .External.graphics(C_layout, num.rows, num.cols, mat, as.integer(num.figures), : invalid graphics state

summary(lca7$posterior, disits=2)

Error in summary(lca7$posterior, disits = 2) : object 'lca7' not found

Question2; Can you add affiliation class number of each sample in the data set?