Warning messages


I am running a cross-lagged path model and have gotten the following warning messages:
Warning messages:
1: In lav_data_full(data = data, group = group, cluster = cluster, :
lavaan WARNING: 15 cases were deleted due to missing values in
exogenous variable(s), while fixed.x = TRUE.
2: In data.matrix(data[case.idx[[g]], ov.idx, drop = FALSE]) :
NAs introduced by coercion
3: In data.matrix(data[case.idx[[g]], ov.idx, drop = FALSE]) :
NAs introduced by coercion
4: In lavaan::lavaan(model = painhrAMod, data = flacchrvafinal, missing = "FIML", :
lavaan WARNING: syntax contains parameters involving exogenous covariates; switching to fixed.x = FALSE

I was wondering if these warnings were impacting my results, and if anyone knows how to fix the NAs introduced by coercion? Also with the warning involving exogenous covariates, how do I add the fixed.x=FALSE to my syntax. Below is what my syntax looks like right now:

painhrAMod <- 'hr5 ~ hr4+flacc4+hrb+nap
flacc5 ~ flacc4+hr4+flaccb+nap
hr4 ~ hr3+flacc3+hrb+nap
flacc4 ~ flacc3+hr3+flaccb+nap
hr3 ~ hr2+flacc2+hrb+fed+nap
flacc3 ~ flacc2+hr2+flaccb+fed+nap
hr2 ~ hr1+flacc1++hrb+fed+nap
flacc2 ~ flacc1+hr1+flaccb+fed+nap
hr1 ~ hr0+flacc0+hrb+fed+nap
flacc1 ~ flacc0+hr0+flaccb+fed+nap
hr0 ~ hrb+flaccb+fed+nap
flacc0 ~ flaccb+hrb+fed+nap
flaccb ~~ hrb
flacc0 ~~ hr0
flacc1 ~~ hr1
flacc2 ~~ hr2
flacc3 ~~ hr3
flacc4 ~~ hr4
flacc5 ~~ hr5'

painhrAFit <- sem(painhrAMod, data=flacchrvafinal, missing="FIML", estimator="MLR", std.lv=T)

summary(painhrAFit, fit.measures=T,standardized = T)

The documentation for sem() under ... says you can specify additional options using name=value. Then the documentation for lavOptions includes fixed.x=FALSE. So just put fixed.x=FALSE in your call to sem(), I think. This might fix all these warnings, possibly.

If you include some data (using dput()) we can run your example.