diff --git a/packages/basic.gblib/services/GBVMService.ts b/packages/basic.gblib/services/GBVMService.ts
index bb69f9dc..8804786b 100644
--- a/packages/basic.gblib/services/GBVMService.ts
+++ b/packages/basic.gblib/services/GBVMService.ts
@@ -251,8 +251,8 @@ export class GBVMService extends GBService {
 
       // Defines local utility BASIC functions.
 
-      const ubound = (array) => {return array.length};
-      const isarray = (array) => {return Array.isArray(array) };
+      const ubound = (gbarray) => {return gbarray.length - 1};
+      const isarray = (gbarray) => {return Array.isArray(gbarray) };
   
       // Proxies remote functions as BASIC functions.
       
diff --git a/packages/basic.gblib/services/SystemKeywords.ts b/packages/basic.gblib/services/SystemKeywords.ts
index 4213ae1d..7f018b1b 100644
--- a/packages/basic.gblib/services/SystemKeywords.ts
+++ b/packages/basic.gblib/services/SystemKeywords.ts
@@ -789,7 +789,7 @@ export class SystemKeywords {
    *
    *  rows = FIND "file.xlsx", "A2=active", "A2 < 12/06/2010 15:00"
    *  i = 1
-   *  do while i < ubound(row)
+   *  do while i <= ubound(row)
    *    row = rows[i]
    *    send sms to "+" + row.mobile, "Hello " + row.name + "! "
    *  loop