diff --git a/DESCRIPTION b/DESCRIPTION
index 3a08a93..00f537f 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -33,6 +33,7 @@ BugReports: https://github.com/SticsRPacks/CroptimizR/issues
 Depends:
     R (>= 4.0.0)
 Imports:
+    Matrix,
     BayesianTools,
     crayon,
     doParallel,
@@ -65,7 +66,7 @@ Suggests:
 VignetteBuilder: 
     knitr
 Remotes:
-    github::florianhartig/BayesianTools/BayesianTools@c953ae2bf8c112f95fdda1a35b2ff33a1f00c208,
+    github::cran/Matrix@1.6-5,
     github::hol430/ApsimOnR,
     github::SticsRPacks/CroPlotR@*release,
     github::SticsRPacks/SticsOnR@*release,
diff --git a/R/compute_eq_const.R b/R/compute_eq_const.R
index 757a9ca..da9f197 100644
--- a/R/compute_eq_const.R
+++ b/R/compute_eq_const.R
@@ -24,16 +24,20 @@ compute_eq_const <- function(forced_param_values, param_values) {
 
     for (irow in 1:nrows) {
 
+      # Backticks are added here and in the following to handle parameters names
+      # including special characters
       expr_ls <-
-        lapply(names(forced_param_values), function(x) paste(x,"<-",forced_param_values[[x]]))
+        lapply(names(forced_param_values), function(x) paste0("`",x,"`","<-",
+                                                              forced_param_values[[x]]))
       names(expr_ls) <- names(forced_param_values)
 
       for (par in names(param_values)) {
-        eval(parse(text = paste(par,"<-",param_values[[irow, par]])))
+        eval(parse(text = paste0("`",par,"`","<-",param_values[[irow, par]])))
       }
       for (par in names(forced_param_values)) {
         eval(parse(text = expr_ls[[par]]))
-        eval(parse(text = paste0("comp_forced_values[irow,\"",par,"\"] <- ",par)))
+        eval(parse(text = paste0("comp_forced_values[irow,\"",par,"\"] <- ",
+                                 "`",par,"`")))
       }
 
     }
diff --git a/R/is_data.R b/R/is_data.R
index c68e8c7..6fbda8d 100644
--- a/R/is_data.R
+++ b/R/is_data.R
@@ -49,7 +49,7 @@
 is.data <- function(data_list) {
 
   # Check data_list format
-  if (!is.list(data_list) || !all(sapply(
+  if (length(data_list)==0 || !is.list(data_list) || !all(sapply(
     data_list,
     function(x) is.data.frame(x)
   ))) {