New error when producing boxplot - r

Question

So I had this script working yesterday on a different data set, an it actually worked once on this data set, but when I tried to combine it with another figure using plot_grid, I got this error:
Error:
T_SHOW_BACKTRACE environmental variable.
Error in grid.Call(L_textBounds, as.graphicsAnnot(x$label), x$x, x$y, :
polygon edge not found
Now when I try to construct the boxplot itself, I get the same error...
Here is my data:
dput(SUICMass)
structure(list(ChillTime = structure(c(1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L,
3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 5L, 5L, 5L, 5L, 5L, 5L,
5L, 5L, 5L, 5L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 7L, 7L,
7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L), .Label = c("2", "4", "6", "24",
"27", "29", "31"), class = "factor"), Mass = c(1.2687, 1.5417,
1.6898, 1.7655, 2.413, 2.0333, 2.0824, 1.2676, 1.4916, 2.1585,
2.2453, 1.3624, 1.2951, 2.4209, 2.0804, 1.9227, 1.9032, 2.1063,
1.7601, 1.9905, 1.9837, 1.6312, 1.8567, 1.4433, 1.9369, 2.1029,
2.0265, 1.3212, 1.2971, 1.5823, 1.4759, 1.2745, 0.714, 1.5693,
1.7906, 1.8607, 1.8851, 1.9192, 1.6307, 1.4269, 1.7011, 0.8249,
1.7198, 1.3939, 1.394, 2.1527, 1.288, 1.4724, 1.5264, 1.6562,
1.5796, 1.4982, 1.2794, 1.6021, 0.6345, 2.4041, 2.0246, 1.8398,
1.349, 2.0156, 1.1563, 2.0462)), .Names = c("ChillTime", "Mass"
), row.names = c(NA, -62L), class = "data.frame")
Here is my code:
library(ggplot2)
library(multcompView)
library(plyr)
library(gridExtra)
library(cowplot)
## Box plot for Susans WMA population
SUICMass <- read.csv('SUICMass_Test_June_28_2017.csv', header = TRUE)
SUICMass$ChillTime <- factor(SUICMass$ChillTime, levels=c("2", "4", "6", "24", "27", "29", "31"))
generate_label_df <- function(SUICMassTUKEY, variable){
# Extract labels and factor levels from Tukey post-hoc
Tukey.levels <- SUICMassTUKEY[[variable]][,4]
Tukey.labels <- data.frame(multcompLetters(Tukey.levels)['Letters'])
#I need to put the labels in the same order as in the boxplot :
Tukey.labels$treatment=rownames(Tukey.labels)
Tukey.labels=Tukey.labels[order(Tukey.labels$treatment) , ]
return(Tukey.labels)
}
SUICMassmodel=lm(SUICMass$Mass~SUICMass$ChillTime )
SUICMassANOVA=aov(SUICMassmodel)
# Tukey test to study each pair of treatment :
SUICMassTUKEY <- TukeyHSD(x=SUICMassANOVA, 'SUICMass$ChillTime', conf.level=0.95)
labels<-generate_label_df(SUICMassTUKEY , "SUICMass$ChillTime")#generate labels using function
names(labels)<-c('Letters','ChillTime')#rename columns for merging
SUICMassyvalue<-aggregate(.~ChillTime, data=SUICMass, max)# obtain letter position for y axis using means
SUICMassfinal<-merge(labels,SUICMassyvalue) #merge dataframes
SUICMassPlot <- ggplot(SUICMass, aes(x = ChillTime, y = Mass)) +
stat_boxplot(geom ='errorbar', width=.2) +
geom_blank() +
theme_bw() +
theme(panel.border = element_rect(fill=NA, colour = "black", size=0.75)) +
theme(axis.text.x = element_text(face="bold")) +
theme(axis.text.y = element_text(face="bold")) +
labs(x = 'Time (weeks)', y = 'Mass (g)') +
ggtitle(expression(atop(bold("Fresh Mass"), atop(italic("(Sarah's - UIC Colony)"))))) +
theme(plot.title = element_text(hjust = 0.5, vjust = -0.6, face='bold')) +
geom_boxplot(fill = 'dodgerblue1', stat = "boxplot") +
geom_text(data = SUICMassfinal, aes(x = ChillTime, y = Mass, label = Letters),vjust=-2,hjust=.5) +
scale_y_continuous(limit = c(0, 3.5))
I can't figure out what the issue is here, because sometimes I can get the script to work and other times not.