Thank you Jon and Karl,

I tried Karl's suggestion and recieved the following errors:

When I tried:

require(xlsx)
write.xlsx(labkey.data, "${fileout:myExcelFile.xlsx}")

I get:

Error executing command
javax.script.ScriptException: javax.script.ScriptException: An error occurred when running the script 'script.R', exit code: 1).
Loading required package: xlsx
Loading required package: rJava
Error : .onLoad failed in loadNamespace() for 'rJava', details:
  call: fun(libname, pkgname)
  error: JAVA_HOME cannot be determined from the Registry
In addition: Warning messages:
1: package 'xlsx' was built under R version 3.2.3
2: package 'rJava' was built under R version 3.2.3
Failed with error: 'package 'rJava' could not be loaded'
Error: could not find function "write.xlsx"
Execution halted

then tried:

require(xlsx)
require(rJava)
write.xlsx(labkey.data, "${fileout:myExcelFile.xlsx}")

and got:

Error executing command
javax.script.ScriptException: javax.script.ScriptException: An error occurred when running the script 'script.R', exit code: 1).
Loading required package: xlsx
Loading required package: rJava
Error : .onLoad failed in loadNamespace() for 'rJava', details:
  call: fun(libname, pkgname)
  error: JAVA_HOME cannot be determined from the Registry
In addition: Warning messages:
1: package 'xlsx' was built under R version 3.2.3
2: package 'rJava' was built under R version 3.2.3
Failed with error: 'package 'rJava' could not be loaded'
Loading required package: rJava
Error : .onLoad failed in loadNamespace() for 'rJava', details:
  call: fun(libname, pkgname)
  error: JAVA_HOME cannot be determined from the Registry
In addition: Warning message:
package 'rJava' was built under R version 3.2.3
Error: could not find function "write.xlsx"
Execution halted



David