I uninstalled and reinstalled with no change… still cannot add it. It stalls out before the dialog box opens. Here is my environment info:

concrete5 Version

Core Version - 8.4.0
Version Installed - 8.4.0
Database Version - 20180524000000

concrete5 Packages

Accordion Pro (1.0.6), Bitter Shop System (1.2.1), Bitter Theme (1.1.6), Counter Up (1.0.2), Image Carousel (0.9.0.8), List files from set (1.0.13), Open Graph Tags Lite (2.1.3), Portfolio Grid (1.0.2), Progressbar (1.0.2), Tallacmans Copyright (1.0)

concrete5 Overrides

None

concrete5 Cache Settings

Block Cache - On
Overrides Cache - Off
Full Page Caching - On - If blocks on the particular page allow it.
Full Page Cache Lifetime - Every 6 hours (default setting).

Server Software

Apache

Server API

cgi-fcgi

PHP Version

7.1.28

PHP Extensions

bcmath, bz2, calendar, cgi-fcgi, Core, ctype, curl, date, dom, exif, fileinfo, filter, ftp, gd, gettext, gmp, hash, iconv, imagick, imap, intl, ionCube Loader, json, libxml, mbstring, mcrypt, mysqli, mysqlnd, OAuth, odbc, openssl, pcntl, pcre, PDO, pdo_mysql, PDO_ODBC, pdo_pgsql, pdo_sqlite, pgsql, Phar, posix, pspell, readline, Reflection, session, SimpleXML, soap, sockets, SPL, sqlite3, standard, tidy, tokenizer, wddx, xml, xmlreader, xmlrpc, xmlwriter, xsl, zip, zlib

PHP Settings

max_execution_time - 30
log_errors_max_len - 1024
max_file_uploads - 20
max_input_nesting_level - 64
max_input_time - 60
max_input_vars - 1000
memory_limit - 256M
post_max_size - 64M
sql.safe_mode - Off
upload_max_filesize - 64M
mysqli.max_links - Unlimited
mysqli.max_persistent - Unlimited
odbc.max_links - Unlimited
odbc.max_persistent - Unlimited
pcre.backtrack_limit - 1000000
pcre.recursion_limit - 100000
pgsql.max_links - Unlimited
pgsql.max_persistent - Unlimited
session.cache_limiter - <i>no value</i>
session.gc_maxlifetime - 7200
soap.wsdl_cache_limit - 5

Unable to add Accordion... progress bar stalls at 95% and no further dialog box opens for input