Error with qe(): handling one predictor and one response variable

**What is the issue?**

Improper handling of the data frame with only 1 predictor variable and 1 response variable.

**Steps to reproduce the error**

data(peFactors)
names(peFactors)

pef <- peFactors[,c(1,8)]

lmout <- qeLin(pef , 'wageinc')

parvsnonparplot(lmout,qeKNN(pef , 'wageinc', 25))

**Expected error**

**1. error message from qeLin()**
Error in eval(predvars, data, env) :
numeric 'envir' arg not of length one

**2 error message from qeKNN()**
Error in getXY(newx, NULL, TRUE, FALSE, object$factorsInfo) :
data must be a data frame


Start by running the reported peFactors subset and the qeLin(), qeKNN(), and parvsnonparplot() calls to reproduce both errors. Trace the data-frame handling around these entry points and compare behavior with inputs containing more predictors. Done means the one-predictor, one-response example completes without either reported error.

Written by the indexing model from the issue text.